@misc{kareem_anaele_olanrewaju_adewale_osondu-okoro_aikulola_falana_gwalani_bodunrin_alaneme_2024, title={Insights into hot deformation of medium entropy alloys: Softening mechanisms, microstructural evolution, and constitutive modelling-a comprehensive review}, volume={29}, ISSN={["2214-0697"]}, DOI={10.1016/j.jmrt.2024.03.011}, abstractNote={The recent discovery of multicomponent principal alloys and the enhanced comprehension of their physical metallurgy have significantly advanced the understanding of microstructure engineering and material selection for high-tech applications. The exceptional combination of characteristics found in MEAs can be attributed to their distinctive phase constitution, which is aided by their multi-principal constituents. These properties are seldom encountered in ordinary alloys. Nevertheless, the use of these materials in their as-cast state is challenging due to issues such as the presence of heterogeneity in their chemical makeup, shrinkage porosity, unrefined dendritic structure, and the presence of a quasi-stable eutectic at grain boundaries. Consequently, the utilization of hot deformation methods for the purpose of achieving uniform and refined microstructures in as-cast MEAs has garnered significant interest as a viable approach to address these limitations. This review provides a comprehensive summary of the hot deformation characteristics of MEAs. Factors such as the alloy composition, the phase constituent, deformation parameters and recrystallization mechanisms were observed to influence the microstructural development and phase transition, flow curve characteristics, and mechanical characteristics of MEAs. Additionally, the use of processing map analysis for the determination of optimal processing zones for the hot deformation of MEAs was appraised. The discussion also encompassed the constitutive model description and machine learning algorithm for the prediction of the governing deformation mechanism and the deformation flow stress. Finally, future research directions are suggested.}, journal={JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T}, author={Kareem, Sodiq Abiodun and Anaele, Justus Uchenna and Olanrewaju, Olajesu Favor and Adewale, Esther Dolapo and Osondu-Okoro, Nkemakolam Chikodinaka and Aikulola, Emmanuel Omosegunfunmi and Falana, Samuel Olumide and Gwalani, Bharat and Bodunrin, Michael Oluwatosin and Alaneme, Kenneth Kanayo}, year={2024}, pages={5369–5401} }
 @article{gwalani_escobar_song_thomas_silverstein_chuang_singh_brady_yamamoto_watkins_et al._2024, title={Mechanisms for high creep resistance in alumina forming austenitic (AFA) alloys}, volume={263}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2023.119494}, abstractNote={Castable alumina forming austenitic (AFA) alloys have demonstrated superior creep life and oxidation resistance at temperatures exceeding 800⁰C. Despite the success in the applicability of these alloys in extreme environments, there is a limited understanding of the deformation modes and the influence of each alloying element guiding the alloy design strategies that could further enhance the creep strength of these AFA alloys, particularly at temperatures at and above 900⁰C. In this study, we reveal the mechanism underpinning the superior creep performance of castable AFA alloys that involves suppressing primary carbide formation through minor compositional modification. This approach results in a three-fold increase in creep strength at 900⁰C and 50 MPa. By employing integrated characterization techniques, we analyzed the microstructures of two AFA alloys, both before and after the creep process. We discovered that the suppression of primary carbides permits the in-situ clustering of now-available interstitial elements such as C, Si, and O during high-temperature creep. This improved solid solution strengthening and reduced stacking fault energy of the alloy. Moreover, it also enabled controlled secondary carbide formation during testing, further improving the creep resistance. These findings underline the important interplay between alloy composition, microstructure, and creep properties, and offer a promising design strategy for developing economical high-temperature Fe-based alloys suitable for advanced applications.}, journal={ACTA MATERIALIA}, author={Gwalani, Bharat and Escobar, Julian and Song, Miao and Thomas, Jonova and Silverstein, Joshua and Chuang, Andrew Chihpin and Singh, Dileep and Brady, Michael P. and Yamamoto, Yukinori and Watkins, Thomas R. and et al.}, year={2024}, month={Jan} }
 @article{gwalani_martin_kautz_guo_lambeets_olszta_battu_malakar_yang_guo_et al._2024, title={Mechanistic understanding of speciated oxide growth in high entropy alloys}, volume={15}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-024-49243-8}, abstractNote={Complex multi-element alloys are gaining prominence for structural applications, supplementing steels, and superalloys. Understanding the impact of each element on alloy surfaces due to oxidation is vital in maintaining material integrity. This study investigates oxidation mechanisms in these alloys using a model five-element equiatomic CoCrFeNiMn alloy, in a controlled oxygen environment. The oxidation-induced surface changes correlate with each element's interactive tendencies with the environment, guided by thermodynamics. Initial oxidation stages follow atomic size and redox potential, with the latter becoming dominant over time, causing composition inversion. The study employs in-situ atom probe tomography, transmission electron microscopy, and X-ray absorption near-edge structure techniques to elucidate the oxidation process and surface oxide structure evolution. Our findings deconvolute the mechanism for compositional and structural changes in the oxide film and will pave the way for a predictive design of complex alloys with improved resistance to oxidation under extreme conditions.}, number={1}, journal={NATURE COMMUNICATIONS}, author={Gwalani, Bharat and Martin, Andrew and Kautz, Elizabeth and Guo, Boyu and Lambeets, S. V. and Olszta, Matthew and Battu, Anil Krishna and Malakar, Aniruddha and Yang, Feipeng and Guo, Jinghua and et al.}, year={2024}, month={Jun} }
 @article{gwalani_li_nittala_choi_reza-e-rabby_atehortua_bhattacharjee_pole_silverstein_song_et al._2024, title={Unprecedented electrical performance of friction-extruded copper-graphene composites}, volume={237}, ISSN={["1873-4197"]}, DOI={10.1016/j.matdes.2023.112555}, abstractNote={Copper-graphene composites show remarkable electrical performance surpassing traditional copper conductors albeit at a micron scale; there are several challenges in demonstrating similar performance at the bulk scale. In this study, we used shear assisted processing and extrusion (ShAPE) to synthesize macro-scale copper-graphene composites with a simultaneously lower temperature coefficient of resistance (TCR) and improved electrical conductivity over copper-only samples. We showed that the addition of 18 ppm of graphene decreased the TCR of C11000 alloy by nearly 11 %. A suite of characterization tools involving scanning and transmission electron microscopy along with atom probe tomography were used to characterize the grain size, crystallographic orientation, structure, and composition of copper grains and graphene additives in the feedstock and processed samples. We posit that the shear extrusion process may have transformed some of the feedstock graphene additives into higher defect-density agglomerates while retaining the structure of others as mono-to-trilete flakes with lower defect density. The combination of these additives with heterogeneous structures may have been responsible for the simultaneous decrease in TCR and enhanced electrical conductivity of the copper-graphene ShAPE composites.}, journal={MATERIALS & DESIGN}, author={Gwalani, Bharat and Li, Xiao and Nittala, Aditya and Choi, Woongjo and Reza-E-Rabby, Md. and Atehortua, Julian Escobar and Bhattacharjee, Arun and Pole, Mayur and Silverstein, Joshua and Song, Miao and et al.}, year={2024}, month={Jan} }
 @article{garg_grewal_sharma_gwalani_arora_2023, title={Circumventing strength-ductility paradox in high entropy alloys through deformation processing}, volume={933}, ISSN={["1873-4669"]}, DOI={10.1016/j.jallcom.2022.167750}, abstractNote={Engineering materials are known to show trade-off between high tensile strength and ductility. The simultaneous enhancement of strength and ductility can make them more appealing for various structural applications. In this study, we demonstrate a facile technique to address the conflicting strength-ductility trade-off in crystalline materials. AlCoCrFeNi high entropy alloy (HEA), one of the most popular multi-principal alloy system, was considered for the investigation. The as-cast AlCoCrFeNi alloy showed a coarse grain microstructure with BCC/B2 phase. The as-cast alloy was subjected to severe plastic deformation using a facile technique known as stationary friction processing (SFP). The SFP for only 15 min resulted in an order of magnitude reduction in the grain size along with BCC to FCC phase transformation. The processed sample demonstrated more than 2 times higher ultimate tensile strength (∼650 MPa) compared to as-cast HEA (∼310 MPa). Further, the ductility of the processed HEA was enhanced from 11 % to 18 %. The combination of fine grain structure along with BCC to FCC transition through SFP enabled exceptional mechanical properties in the HEA. This approach can easily be extended to other alloy systems for designing high tensile strength and superior ductility.}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, author={Garg, Mayank and Grewal, Harpreet S. and Sharma, Ram K. and Gwalani, Bharat and Arora, Harpreet S.}, year={2023}, month={Feb} }
 @article{fulmali_patnaik_rathore_bhattacharjee_gwalani_ray_prusty_2023, title={Enhanced extreme temperature bending and delamination resistance of GFRP composites through z-directional aligned nano-reinforcement: Emphasizing the effects of CNT functionalization}, volume={244}, ISSN={["1879-1050"]}, DOI={10.1016/j.compscitech.2023.110272}, abstractNote={Laminated FRP composites' weak out-of-plane mechanical performance prevents their usage in structural applications where homogeneous load bearing qualities are required. In this regard, a z-directional nano-reinforcement approach was implemented to mitigate the poor in-plane shear and out-of-plane response of laminated glass fiber epoxy (GE) composites under extreme in-service temperature conditions. CNT and functionalized CNT (FCNT) were dispersed separately in the GE composites' epoxy matrix and subjected to a z-direction electric field alignment treatment. Flexural and short beam shear tests of GE composites with random and aligned CNT/FCNT were performed at room temperature, in-situ cryogenic and elevated temperature conditions (RT, CT and ET, respectively). GE composite with aligned FCNT (A-FCNT-GE) consistently outperformed other composites at all considered temperatures with remarkable improvements, specifically ∼39%, ∼41% and ∼47% in flexural strength, and ∼30%, ∼30%, and ∼24% in interlaminar shear strength (ILSS) over the control GE composite at RT, CT and ET, respectively. Dynamic mechanical thermal analysis suggested that the synergetic impact of functionalization and alignment of FCNT improved the viscoelastic properties of the A-FCNT-GE composite across a range of temperature conditions. Fractography analysis provided insight into the interfacial and interlayer mechanisms that improved the extreme temperature condition mechanical performance. The reliability of electric field aligned FCNT as a z-directional nano-reinforcement in laminated composites at extreme temperature conditions was established in this study.}, journal={COMPOSITES SCIENCE AND TECHNOLOGY}, author={Fulmali, Abhinav Omprakash and Patnaik, Satyaroop and Rathore, Dinesh Kumar and Bhattacharjee, Debashish and Gwalani, Bharat and Ray, Bankim Chandra and Prusty, Rajesh Kumar}, year={2023}, month={Nov} }
 @article{dasari_sharma_jiang_gwalani_lin_lo_gorsse_yeh_srinivasan_banerjee_2023, title={Exceptional enhancement of mechanical properties in high-entropy alloys via thermodynamically guided local chemical ordering}, volume={120}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.2211787120}, abstractNote={Understanding the local chemical ordering propensity in random solid solutions, and tailoring its strength, can guide the design and discovery of complex, paradigm-shifting multicomponent alloys. First, we present a simple thermodynamic framework, based solely on binary enthalpies of mixing, to select optimal alloying elements to control the nature and extent of chemical ordering in high-entropy alloys (HEAs). Next, we couple high-resolution electron microscopy, atom probe tomography, hybrid Monte-Carlo, special quasirandom structures, and density functional theory calculations to demonstrate how controlled additions of Al and Ti and subsequent annealing drive chemical ordering in nearly random equiatomic face-centered cubic CoFeNi solid solution. We establish that short-range ordered domains, the precursors of long-range ordered precipitates, inform mechanical properties. Specifically, a progressively increasing local order boosts the tensile yield strengths of the parent CoFeNi alloy by a factor of four while also substantially improving ductility, which breaks the so-called strength–ductility paradox. Finally, we validate the generality of our approach by predicting and demonstrating that controlled additions of Al, which has large negative enthalpies of mixing with the constituent elements of another nearly random body-centered cubic refractory NbTaTi HEA, also introduces chemical ordering and enhances mechanical properties.}, number={23}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Dasari, Sriswaroop and Sharma, Abhishek and Jiang, Chao and Gwalani, Bharat and Lin, Wei-Chih and Lo, Kai-Chi and Gorsse, Stephane and Yeh, An-Chou and Srinivasan, Srivilliputhur G. and Banerjee, Rajarshi}, year={2023}, month={Jun} }
 @article{srivastava_das_tamayo_li_pole_gwalani_soulami_santos_kappagantula_reza-e-rabby_2023, title={Extent of interlocking and metallurgical bonding in friction riveting of aluminum alloy to steel}, volume={8}, ISSN={["1433-3015"]}, DOI={10.1007/s00170-023-12111-8}, abstractNote={In this study, the joining of 6061-T6 aluminum alloy and DP590 steel using a M42 steel rivet via friction riveting technique is investigated. The surface morphology and microstructure characterization reveal the formation of an anchor zone that imparts mechanical interlock as well as the formation of metallurgical bonds at the interface of aluminum and steel. A combination of interlocking and bonding results in the achievement of a high load-carrying capacity of 5.7 kN during lap shear testing at room temperature. A finite element-based computational model was developed which accurately predicted the lap shear response of the joint. The model revealed that the metallurgical bond formed during fric-riveting adds 39% peak load strength to the joint. An extensive microstructural investigation, post-lap-shear fractography, and the modeling results, together provided insights on the joint failure mechanism. This study highlights that friction riveting is a promising method for aluminum-to-steel dissimilar joining, which is important for lighweighing automotive vehicles for energy efficiency.}, journal={INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY}, author={Srivastava, Abhinav and Das, Hrishikesh and Tamayo, Daniel Ramirez and Li, Lei and Pole, Mayur and Gwalani, Bharat and Soulami, Ayoub and Santos, Jorge F. F. and Kappagantula, Keerti S. S. and Reza-E-Rabby, Md.}, year={2023}, month={Aug} }
 @article{srivastava_das_tamayo_li_pole_gwalani_soulami_santos_kappagantula_reza-e-rabby_2023, title={Extent of interlocking and metallurgical bonding in friction riveting of aluminum alloy to steel (vol 128, pg 7, 2023)}, volume={128}, ISSN={["1433-3015"]}, DOI={10.1007/s00170-023-12219-x}, number={7-8}, journal={INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY}, author={Srivastava, Abhinav and Das, Hrishikesh and Tamayo, Daniel Ramirez and Li, Lei and Pole, Mayur and Gwalani, Bharat and Soulami, Ayoub and Santos, Jorge F. and Kappagantula, Keerti S. and Reza-E-Rabby, Md.}, year={2023}, month={Oct}, pages={2913–2913} }
 @article{thomas_perumal_padmanaban_ma_kumar_sharma_ayyagari_gwalani_arora_2023, title={High strain-rate driven nano-tubular architecture in NiMn alloy for supercapacitor electrodes}, volume={465}, ISSN={["1873-3212"]}, DOI={10.1016/j.cej.2023.143008}, abstractNote={Electrochemical energy storage (EES) devices play a crucial role in our pursuit of non-polluting, green technologies. With the characteristic short ion-diffusion length, nano-scale materials are considered promising for the realization of high-performance EES. In contrast, existing nano-textured electrodes' inadequate ion-accessible surface area and laborious multi-step synthesis technology limits their overall performance. Herein, we provide the first demonstration of sub-homologous temperature solid-state nano-moulding in a crystalline alloy, resulting in a highly ordered hierarchical nano-tubular architecture with outstanding electrochemical energy storage. Benefitting from increased material fluidity at a high strain rate, a short burst of physical deformation facilitated the material flow into the nano-moulds. The chemically dealloyed nano-tubular electrode demonstrated excellent volumetric specific capacitance of ∼1000 F/cm3 at 5.5 A/cm3 current density. A symmetric supercapacitor device showcased an exceptional energy density of ∼90 Wh/L at a power density of ∼0.5 kW/L and excellent cyclic stability of 94% after 10,000 cycles. The device-level technology readiness is demonstrated by successfully integrating multiple small devices to operate high-power electronic components, setting the way forward for advanced energy storage applications.}, journal={CHEMICAL ENGINEERING JOURNAL}, author={Thomas, A. and Perumal, G. and Padmanaban, D. B. and Ma, Xiaolong and Kumar, A. and Sharma, R. K. and Ayyagari, A. and Gwalani, B. and Arora, H. S.}, year={2023}, month={Jun} }
 @article{kautz_zelenyuk_gwalani_olszta_phillips_manard_kimblin_harilal_2023, title={Impact of environmental oxygen on nanoparticle formation and agglomeration in aluminum laser ablation plumes}, volume={159}, ISSN={["1089-7690"]}, url={https://doi.org/10.1063/5.0167400}, DOI={10.1063/5.0167400}, abstractNote={The role of ambient oxygen gas (O2) on molecular and nanoparticle formation and agglomeration was studied in laser ablation plumes. As a lab-scale surrogate to a high explosion detonation event, nanosecond laser ablation of an aluminum alloy (AA6061) target was performed in atmospheric pressure conditions. Optical emission spectroscopy and two mass spectrometry techniques were used to monitor the early to late stages of plasma generation to track the evolution of atoms, molecules, clusters, nanoparticles, and agglomerates. The experiments were performed under atmospheric pressure air, atmospheric pressure nitrogen, and 20% and 5% O2 (balance N2), the latter specifically with in situ mass spectrometry. Electron microscopy was performed ex situ to identify crystal structure and elemental distributions in individual nanoparticles. We find that the presence of ≈20% O2 leads to strong AlO emission, whereas in a flowing N2 environment (with trace O2), AlN and strong, unreacted Al emissions are present. In situ mass spectrometry reveals that as O2 availability increases, Al oxide cluster size increases. Nanoparticle agglomerates formed in air are found to be larger than those formed under N2 gas. High-resolution transmission electron microscopy demonstrates that Al2O3 and AlN nanoparticle agglomerates are formed in both environments; indicating that the presence of trace O2 can lead to Al2O3 nanoparticle formation. The present results highlight that the availability of O2 in the ambient gas significantly impacts spectral signatures, cluster size, and nanoparticle agglomeration behavior. These results are relevant to understanding debris formation in an explosion event, and interpreting data from forensic investigations.}, number={17}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Kautz, Elizabeth J. and Zelenyuk, Alla and Gwalani, Bharat and Olszta, Matthew J. and Phillips, Mark C. and Manard, Manuel J. and Kimblin, Clare W. and Harilal, Sivanandan S.}, year={2023}, month={Nov} }
 @article{sharma_dasari_ingale_jiang_gwalani_srinivasan_banerjee_2023, title={Introducing local chemical ordering to trigger a planar-slip-initiated strain-hardening mechanism in high entropy alloys}, volume={258}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2023.119248}, abstractNote={This study demonstrates that we can break the strength-ductility paradox in face-centered cubic (FCC) high-entropy alloys (HEAs) by introducing local chemical ordering. Employing high-resolution transmission electron microscopy, atom probe tomography, and electron-chanelling contrast imaging in CoFeNi and CoCrFeNi HEAs with (Al/Ti) additions, we report a planar-slip-induced strain-hardening mechanism that operates at significantly higher stresses compared to the well-known transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) mechanisms. Our results provide clear evidence that the introduction of chemical ordering in HEAs promotes localized slip along multiple {111} planes. Importantly, the interactions between planar slip activities on non-parallel {111} planes triggers a dynamic Hall-Petch like effect that continually refines the slip length. This is in contrast to hexagonal closed packed (HCP) alloys, where such glide plane softening typically causes catastrophic failure. Consequently, this newly identified mechanism increases the yield-strength while maintaining a better combination of strength and ductility in our FCC-based HEAs. These findings, together with our previous results [33,34], establish a compelling alloy design paradigm for the discovery of FCC-based HEAs that can circumvent the strength-ductility paradox.}, journal={ACTA MATERIALIA}, author={Sharma, Abhishek and Dasari, Sriswaroop and Ingale, Tirthesh and Jiang, Chao and Gwalani, Bharat and Srinivasan, Srivilliputhur G. and Banerjee, Rajarshi}, year={2023}, month={Oct} }
 @misc{kautz_gwalani_yu_varga_geelhood_devaraj_senor_2023, title={Investigating zirconium alloy corrosion with advanced experimental techniques: A review}, volume={585}, ISSN={["1873-4820"]}, DOI={10.1016/j.jnucmat.2023.154586}, abstractNote={Zirconium-based alloys (Zr alloys) are key materials in the nuclear industry due to their thermal stability, mechanical durability, and low thermal neutron cross section. However, corrosion can significantly impact their integrity and lifespan. The corrosion of Zr alloys involves dynamic processes such as phase transformations, element redistributions, stress accumulation, volumetric changes, and formation of defects in oxide films. Recent advancements in experimental techniques have improved our understanding of these phenomena and our ability to predict material behavior in extreme environments. This review focuses on the knowledge gained through the application of advanced experimental techniques to enhance the understanding of zirconium alloy oxidation and hydrogen pick-up in nuclear environments.}, journal={JOURNAL OF NUCLEAR MATERIALS}, author={Kautz, Elizabeth and Gwalani, Bharat and Yu, Zefeng and Varga, Tamas and Geelhood, Kenneth and Devaraj, Arun and Senor, David}, year={2023}, month={Nov} }
 @article{garg_grewal_sharma_gwalani_arora_2023, title={Limiting oxidation of high entropy alloy via high strain-rate deformation: Insights from electrochemical impedance spectroscopy}, volume={294}, ISSN={["1879-3312"]}, DOI={10.1016/j.matchemphys.2022.127017}, abstractNote={Material processing is often performed to form a fine grain structure with uniform distribution of mechanical properties. In the present study, a one-step solid phase processing technique that take advantage of in-situ reactive metallurgy, called stationary friction processing (SFP), is proposed to improve high temperature oxidation performance of AlCoCrFeNi high entropy alloy (HEA). The strategy involves producing a multi-phase fine-grain microstructure through SFP. The processed specimen retarded the oxidation kinetics by ∼52%. The electrochemical impedance spectroscopy coupled with transmission electron microscopy provided new insights into the physico-chemical nature and performance of the oxide-scale. Processed specimen demonstrated an increase in the polarization resistance with the immersion time while unprocessed HEA showed the reverse trend. The excellent oxidation performance was attributed to thin, adherent and uniform oxide layer on the processed HEA.}, journal={MATERIALS CHEMISTRY AND PHYSICS}, author={Garg, Mayank and Grewal, Harpreet S. and Sharma, Ram K. and Gwalani, Bharat and Arora, Harpreet S.}, year={2023}, month={Jan} }
 @article{song_liu_ma_pang_olszta_silverstein_pallaka_sushko_mathaudhu_powell_et al._2023, title={Mass transport in a highly immiscible alloy on extended shear deformation}, volume={134}, ISSN={["1941-1162"]}, DOI={10.1016/j.jmst.2022.06.029}, abstractNote={Forced mixing to a single-phase or supersaturated solid solution (SSS) and its prerequisite microstructure evolution in immiscible systems has been a focus of research for fundamental science and practical applications. Controlling the formation of SSS by shear deformation could enable a material design beyond conventional equilibrium microstructure in immiscible systems. Here, a highly immiscible Cu–50 at.% Cr binary alloy (mixing enthalpy of ∼20 kJ mol−1) was employed to investigate the microstructure evolution and localized tendencies of SSS during severe shear deformation. Our results demonstrate the dislocation mediated microstructural refinement process in each phase of the binary alloy and the mechanisms associated with localized solute supersaturation as a function of shear strain. Pronounced grain refinement in the softer Cu phase occurs owing to the strain localization driving the preferential dynamic recrystallization. The grain refinement of the Cr phase, however, is enabled by the progressive evolution of grain lamination, splitting, and fragmentation as a function of shear strain. The solute supersaturation is found to be strongly dependent on the local environments that affect the dislocation activity, including the level of microstructure refinement, the interfacial orientation relationship, the mechanical incompatibility, and the localized preferential phase oxidation. Ab initio simulations confirm that it is more favorable to oxidize Cr than Cu at incoherent Cu/Cr interfaces, limiting the mass transport on an incoherent boundary. Our results unveil the mechanism underpinning the non-equilibrium mass transport in immiscible systems upon severe deformation that can be applied to produce immiscible alloys with superior mechanical properties.}, journal={JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY}, author={Song, Miao and Liu, Jia and Ma, Xiaolong and Pang, Qin and Olszta, Matthew J. and Silverstein, Joshua and Pallaka, Madhusudhan R. and Sushko, Peter V and Mathaudhu, Suveen N. and Powell, Cynthia and et al.}, year={2023}, month={Jan}, pages={197–208} }
 @article{escobar_silverstein_ishrak_li_soulami_li_yu_mathaudhu_ortiz_koch_et al._2023, title={Microstructural evolution in shear-punch tests: A comparative study of pure Cu and Cu-Cr alloy}, volume={886}, ISSN={["1873-4936"]}, url={https://doi.org/10.1016/j.msea.2023.145715}, DOI={10.1016/j.msea.2023.145715}, abstractNote={Understanding the mechanisms behind microstructural evolution during shear deformation has been a long-standing area of interest. However, establishing a connection between microstructure, mechanical properties, and the extent of shear deformation is challenging and requires refined experimental approaches. Shear-punch testing (SPT) provides a controlled method to introduce shear into small volumes of material that later can be subjected to detailed microstructural characterization. In this study, we utilize an SPT device to induce shear deformation to pure copper (Cu) and a binary copper-chromium (Cu-Cr) alloy. Electron backscatter diffraction and transmission electron microscopy were used to study the mechanisms of plastic deformation after SPT. Our results indicate that shear deformation of pure Cu produces a dense network of intercepting microshear bands upon sustained deformation. Twin boundaries in annealed Cu undergo transformation into high-angle grain boundaries due to simultaneous deviation from the axis-angle pair condition of 60° misorientation on [111] direction. The presence of 50 vol% Cr particles in the soft Cu matrix altered the shear deformation mechanism. Preferential deformation of the Cu matrix in Cu-Cr alloy led to accelerated shear-induced formation of low and high-angle grain boundaries and subsequent grain refinement. Comparatively, insignificant grain refinement occurred in pure Cu samples even at a strain ∼10 times larger (ε = 4.73) than that of the Cu-Cr case (ε = 0.42). This study sheds light on the microstructural evolution of Cu during shear deformation and highlights the significant influence of a hard second phase in modifying the microstructural response mechanisms of a softer matrix.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Escobar, Julian and Silverstein, Joshua and Ishrak, Farhan and Li, Lei and Soulami, Ayoub and Li, Shuang and Yu, Anqi and Mathaudhu, Suveen and Ortiz, Angel and Koch, Carl and et al.}, year={2023}, month={Oct} }
 @article{pole_lu_ajantiwalay_olszta_tripathi_yu_mehta_wang_ma_devaraj_et al._2023, title={Modes of strain accommodation in Cu-Nb multilayered thin film on indentation and cyclic shear}, volume={37}, ISSN={["2468-0230"]}, DOI={10.1016/j.surfin.2023.102712}, abstractNote={Two-phase layered thin films with a high density of semi-coherent interfaces exhibit excellent mechanical properties and thermal stability. In this study, a magnetron-sputtered Cu-Nb dual-layered thin film (∼500 nm for Cu and ∼150 nm for Nb) having an amorphous interface between Cu and Nb with a high density of aligned growth twins in Cu is subjected to severe surface deformation. The material is loaded using indentation and cyclic shear under tribological testing. The strain accommodation in the subsurface microstructure after deformation varies based on the local structure and deformation mode. Grain refinement and crack formations in the stressed region of the Nb layer and localized crystallization of the amorphous interface are observed after indentation and scratch testing. Pronounced detwinning of growth twins in the Cu layer under the cyclic shear strain leaves large dislocations sites and loops which are observed both by high-resolution transmission electron microscopy and experiment-guided molecular dynamic (MD) simulations. Our simulations provided insights into understanding the pathway for the detwinning process under cyclic shear loading.}, journal={SURFACES AND INTERFACES}, author={Pole, Mayur and Lu, Zexi and Ajantiwalay, Tanvi Anil and Olszta, Matthew and Tripathi, Shalini and Yu, Anqi and Mehta, Hardeep and Wang, Tianhao and Ma, Xiaolong and Devaraj, Arun and et al.}, year={2023}, month={Apr} }
 @article{li_rao_atwi_sivakumar_gwalani_gray_han_everett_ajantiwalay_murugesan_et al._2023, title={Non-polar ether-based electrolyte solutions for stable high-voltage non-aqueous lithium metal batteries}, url={https://doi.org/10.1038/s41467-023-36647-1}, DOI={10.1038/s41467-023-36647-1}, abstractNote={Abstract}, journal={Nature Communications}, author={Li, Zheng and Rao, Harsha and Atwi, Rasha and Sivakumar, Bhuvaneswari M. and Gwalani, Bharat and Gray, Scott and Han, Kee Sung and Everett, Thomas A. and Ajantiwalay, Tanvi A. and Murugesan, Vijayakumar and et al.}, year={2023}, month={Feb} }
 @article{thomas_kumar_perumal_sharma_manivasagam_popat_ayyagari_yu_tripathi_buck_et al._2023, title={Oxygen-Vacancy Abundant Nanoporous Ni/NiMnO3/MnO2@NiMn Electrodes with Ultrahigh Capacitance and Energy Density for Supercapacitors}, volume={1}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.2c16818}, abstractNote={High-performance energy storage devices (HPEDs) play a critical role in the realization of clean energy and thus enable the overarching pursuit of nonpolluting, green technologies. Supercapacitors are one class of such lucrative HPEDs; however, a serious limiting factor of supercapacitor technology is its sub-par energy density. This report presents hitherto unchartered pathway of physical deformation, chemical dealloying, and microstructure engineering to produce ultrahigh-capacitance, energy-dense NiMn alloy electrodes. The activated electrode delivered an ultrahigh specific-capacitance of 2700 F/cm3 at 0.5 A/cm3. The symmetric device showcased an excellent energy density of 96.94 Wh/L and a remarkable cycle life of 95% retention after 10,000 cycles. Transmission electron microscopy and atom probe tomography studies revealed the evolution of a unique hierarchical microstructure comprising fine Ni/NiMnO3 nanoligaments within MnO2-rich nanoflakes. Theoretical analysis using density functional theory showed semimetallic nature of the nanoscaled oxygen-vacancy-rich NiMnO3 structure, highlighting enhanced carrier concentration and electronic conductivity of the active region. Furthermore, the geometrical model of NiMnO3 crystals revealed relatively large voids, likely providing channels for the ion intercalation/de-intercalation. The current processing approach is highly adaptable and can be applied to a wide range of material systems for designing highly efficient electrodes for energy-storage devices.}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Thomas, Arpit and Kumar, Ambrish and Perumal, Gopinath and Sharma, Ram Kumar and Manivasagam, Vignesh and Popat, Ketul and Ayyagari, Aditya and Yu, Anqi and Tripathi, Shalini and Buck, Edgar and et al.}, year={2023}, month={Jan} }
 @article{ajantiwalay_ma_yu_pole_silverstein_mathaudhu_devaraj_gwalani_2023, title={Shear deformation of pure-Cu and Cu/Nb nano-laminates using micromechanical testing}, volume={230}, ISSN={["1872-8456"]}, DOI={10.1016/j.scriptamat.2023.115403}, abstractNote={Solid phase processing by introducing shear deformation into materials can result in unique microstructure evolution and enhanced mechanical properties, especially for immiscible systems such as Cu/Nb. To better understand the correlation between microstructure and deformation behavior during shear, a dedicated testing design of stress localization at predicted sites is necessary. In this study, a specialized S-shaped specimen geometry is implemented to apply localized simple-shear loading in pure-Cu and Cu/Nb accumulative roll-bonded nanolaminates. The nanoscale microstructure and proximity of interfaces in Cu/Nb offer a ∼2.8-fold increase in shear stresses than pure-Cu. In pure-Cu, the plastic instability causes shear banding and an in-plane lattice rotation. In Cu/Nb, a partial bending of the interfaces occurred, resulting in a localized lattice rotation. The adapted geometry for micro-scale specimens thus successfully captures the shear deformation at predicted sites in two distinct material systems and could potentially be a powerful technique to study the deformation mechanisms.}, journal={SCRIPTA MATERIALIA}, author={Ajantiwalay, Tanvi and Ma, Xiaolong and Yu, Anqi and Pole, Mayur and Silverstein, Joshua and Mathaudhu, Suveen and Devaraj, Arun and Gwalani, Bharat}, year={2023}, month={Jun} }
 @article{nittala_smith_gwalani_silverstein_kraft_kappagantula_2023, title={Simultaneously improved electrical and mechanical performance of hot-extruded bulk scale aluminum-graphene wires}, volume={293}, ISSN={["1873-4944"]}, DOI={10.1016/j.mseb.2023.116452}, abstractNote={Aluminum-based alloys are highly sought after as lightweight alternatives in electric grid applications. Improving the electrical conductivity of aluminum alloys has the potential to increase the energy efficiency of power transport. The hot extrusion process was used to synthesize AA1100 alloy with low-cost reduced graphene oxide nanoparticles to manufacture ultra-conductive aluminum composites in this study. The effects of graphene content on the electrical and mechanical performance of the composites were evaluated. The macroscale AA1100/graphene wires demonstrated a 2.1% enhancement in electrical conductivity at 20 °C, while the ultimate tensile strength increased by 6.1%. A Zener-Hollomon model was used to confirm the in-process exfoliation of the agglomerated graphene nanoparticle feedstock into high electrical conductivity graphene-like flakes during extrusion. The graphene-like flakes may have provided high-velocity carrier pathways leading to the enhanced electrical performance of the alloy. Transmission electron microscopy at aluminum-graphene interfaces ensures the preclusion of detrimental carbide formation during composite synthesis while confirming the structure of graphene-like flakes. The in-process exfoliation provides an economically viable technique to produce bulk scale “graphinated” aluminum composites for advanced applications and this can also be applied more generally to other alloy systems.}, journal={MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS}, author={Nittala, Aditya and Smith, Jacob and Gwalani, Bharat and Silverstein, Joshua and Kraft, Frank F. and Kappagantula, Keerti}, year={2023}, month={Jul} }
 @inproceedings{frazier_gwalani_escobar_silverstein_kappagantula_2022, place={Cham}, title={A Finite Difference Analysis of the Effect of Graphene Additions on the Electrical Conductivity of Polycrystalline Copper}, DOI={10.1007/978-3-030-92381-5_67}, abstractNote={A finite difference method was used to explore the effect of graphene on the bulk electrical conductivity of copper-graphene composites. In this capacity, grain orientation information from pure copper and copper-graphene composites was used to generate synthetic 3D microstructuresMicrostructure. The electrical conductivity of these microstructures was calculated using the finite difference method assuming different average grain sizes. From these calculations, we demonstrate that when high-conductivity grain boundaries are present within the microstructureMicrostructure arising from the presence of graphene, an increase in the bulk electrical conductivity is observed. On the other hand, the difference in textures between copper and copper-graphene composites may not account for a significant difference in bulk electrical conductivity. In comparison, the copper grain size has a considerably larger effect on electrical conductivity as previously anticipated. This is one of the first demonstrations of a physical basis for enhanced conductivity composites and presents pathways for further investigations on the effects of composite microstructural features, material interfaces, and graphene content on electrical performance.}, booktitle={TMS 2022 151st Annual Meeting & Exhibition Supplemental Proceedings}, publisher={Springer}, author={Frazier, William and Gwalani, Bharat and Escobar, Julian and Silverstein, Joshua and Kappagantula, Keerti S.}, year={2022}, pages={705–712} }
 @article{frazier_li_gwalani_silverstein_devaraj_soulami_sushko_2022, title={An Approach for the Microstructure-Sensitive Simulation of Shear-Induced Deformation and Recrystallization in Al–Si Alloys}, volume={53}, DOI={10.1007/s11661-022-06606-4}, journal={Metallurgical and Materials Transactions A}, author={Frazier, William E. and Li, Lei and Gwalani, Bharat and Silverstein, Joshua and Devaraj, Arun and Soulami, Ayoub and Sushko, Peter V.}, year={2022}, pages={1450–1461} }
 @article{gwalani_pole_whalen_li_yu_o'callahan_nittala_wang_tao_kappagantula_2022, title={Atomistic understanding of extreme strain shear deformation of Copper-Graphene composites}, volume={198}, url={https://doi.org/10.1016/j.carbon.2022.07.013}, DOI={10.1016/j.carbon.2022.07.013}, abstractNote={Copper-Graphene (Cu-Gr) composites demonstrate high strength, lubricity, and enhanced electrical and thermal conductivity compared to pure copper. A homogeneous dispersion of graphene/graphitic domains in Cu is highly desirable, which can be achieved by solid-state shear-assisted processing. A detailed understanding of structure evolution of Cu-Gr under deformation is needed. Here we subjected Gr coated Cu foils to high strain shear deformation using a tribometer to observe the distribution and reallocation of Gr in Cu matrix. A rupture and smearing of Gr layer into Cu were observed reducing the Cu grain size from 67 ± 14 μm to <10 nm, in maximum shear region close to surface. While a gradual strain accumulation further below resulted in grain rotations and dynamic recrystallization. During deformation, the Gr film was first observed to fracture into flakes and then embed into the Cu matrix. Graphitic domains observed in the Cu evinced the metastable composite microstructure with a sandwich layer of Cu2O on the interface. The local conductance, measured by conductive atomic force microscopy, shows a fivefold increase in Cu-Gr composite region compared to pure Cu. Our study shows the feasibility of shear processing to create fine-grained Cu-Gr composites with enhanced conductivity.}, journal={Carbon}, publisher={Elsevier BV}, author={Gwalani, Bharat and Pole, Mayur and Whalen, Kate and Li, Shuang and Yu, Anqi and O'Callahan, Brian and Nittala, Aditya and Wang, Chongmin and Tao, Jinhui and Kappagantula, Keerti}, year={2022}, month={Oct}, pages={63–69} }
 @article{yu_pole_atehortua_bozhilov_liu_silverstein_mukherjee_mathaudhu_devaraj_gwalani_2022, title={Decoupling of strain and temperature effects on microstructural evolution during high shear strain deformation}, url={https://doi.org/10.1016/j.mtla.2022.101402}, DOI={10.1016/j.mtla.2022.101402}, abstractNote={The interplay between defect generation by shear strain and defect annihilation by local heating is difficult to predict in shear-assisted processing techniques. Here, we decoupled the effects of high shear strain and external heating in an immiscible Cu-Nb alloy using a pin-on-disk tribometer to mimic the microstructural evolution of material during solid-phase processing. The change in sub-surface deformation, strain distribution, and redistribution of the second phase as a function of temperature were examined using transmission electron microscopy and atom probe tomography. Zener-Hollomon parameter is used to semi-quantify the deformation of Cu-Nb alloys as a function of strain and temperature.}, journal={Materialia}, author={Yu, Anqi and Pole, Mayur and Atehortua, Julian D Escobar and Bozhilov, Krassimir and Liu, Jia and Silverstein, Joshua A and Mukherjee, Sundeep and Mathaudhu, Suveen and Devaraj, Arun and Gwalani, Bharat}, year={2022}, month={May} }
 @article{gwalani_pang_yu_fu_li_pole_roach_mathaudhu_ajantiwalay_efe_et al._2022, title={Extended Shear Deformation of the Immiscible Cu–Nb Alloy Resulting in Nanostructuring and Oxygen Ingress with Enhancement in Mechanical Properties}, volume={7}, url={https://doi.org/10.1021/acsomega.1c07368}, DOI={10.1021/acsomega.1c07368}, abstractNote={Deformation processing of immiscible systems is observed to disrupt thermodynamic equilibrium, often resulting in nonequilibrium microstructures. The microstructural changes including nanostructuring, hierarchical distribution of phases, localized solute supersaturation, and oxygen ingress result from high-strain extended deformation, causing a significant change in mechanical properties. Because of the dynamic evolution of the material under large strain shear load, a detailed understanding of the transformation pathway has not been established. Additionally, the influence of these microstructural changes on mechanical properties is also not well characterized. Here, an immiscible Cu-4 at. % Nb alloy is subjected to a high-strain shear deformation (∼200); the deformation-induced changes in the morphology, crystal structure, and composition of Cu and Nb phases as a function of total strain are characterized using transmission electron microscopy and atom probe tomography. Furthermore, a multimodal experiment-guided computational approach is used to depict the initiation of deformation by an increase in misorientation boundaries by crystal plasticity-based grain misorientation modeling (strain ∼0.6). Then, co-deformation and nanolamination of Cu and Nb are envisaged by a finite element method-based computational fluid dynamic model with strain ranging from 10 to 200. Finally, the experimentally observed amorphization of the severely sheared supersaturated Cu–Nb–O phase was validated using the first principle-based simulation using density functional theory while highlighting the influence of oxygen ingress during deformation. Furthermore, the nanocrystalline microstructure shows a >2-fold increase in hardness and compressive yield strength of the alloy, elucidating the potential of deformation processing to obtain high-strength low-alloyed metals. Our approach presents a step-by-step evolution of a microstructure in an immiscible alloy undergoing severe shear deformation, which is broadly applicable to materials processing based on friction stir, extrusion, rolling, and surface shear deformation under wear and can be directly applied to understanding material behavior during these processes.}, number={16}, journal={ACS Omega}, publisher={American Chemical Society (ACS)}, author={Gwalani, Bharat and Pang, Qin and Yu, Anqi and Fu, Wenkai and Li, Lei and Pole, Mayur and Roach, Christian and Mathaudhu, Suveen N. and Ajantiwalay, Tanvi and Efe, Mert and et al.}, year={2022}, month={Apr}, pages={13721–13736} }
 @article{wang_gwalani_song_ma_liu_das_silverstein_whalen_2022, title={Extreme shear deformation enables ultra-fast riveting of high strength aluminum alloys}, volume={75}, DOI={10.1016/j.jmapro.2022.01.046}, abstractNote={Dispersed nano-precipitates strengthen high-strength aluminum (Al) alloys but reduce ductility and formability. Joining these alloys with conventional impact (or driven) riveting has long been a challenge because the rivets may crack in ambient conditions. Rotating hammer riveting (RHR) was developed to rivet fully hardened high-strength Al alloys 2024-T351 and 7075-T6. RHR eliminates the need to soften 7075 rivets by preheating or to store 2024 rivets at low temperature to preserve the annealed condition. Avoiding cracked rivet heads and shanks during RHR is attributed to high-strain-rate plastic deformation, which promotes dynamic recrystallization of grains and amorphization of second phases; this mitigates stress concentration and prevents microvoids. Meanwhile, the coherent solute atom clusters in the Al matrix are sheared by dislocation movement, not coarsened, because the thermal cycle is short (10−1 s). RHR obviates time- and cost-intensive prior and post-processing heat treatments, achieving high integrity between riveted and assembled components.}, journal={Journal of Manufacturing Processes}, author={Wang, Tianhao and Gwalani, Bharat and Song, Miao and Ma, Xiaolong and Liu, Tingkun and Das, Hrishikesh and Silverstein, Joshua and Whalen, Scott}, year={2022}, month={Mar}, pages={814–825} }
 @article{chen_hu_setyawan_gwalani_sushko_mathaudhu_2022, title={Formation and dissociation of shear-induced high-energy dislocations: insight from molecular dynamics simulations}, volume={30}, DOI={10.1088/1361-651X/ac44a5}, abstractNote={Abstract}, number={2}, journal={Modelling and Simulation in Materials Science and Engineering}, author={Chen, Nanjun and Hu, Shenyang and Setyawan, Wahyu and Gwalani, Bharat and Sushko, Peter V. and Mathaudhu, Suveen N.}, year={2022}, pages={025012} }
 @article{kautz_zelenyuk_gwalani_phillips_harilal_2022, title={Gas-phase oxidation and nanoparticle formation in multi-element laser ablation plumes}, volume={10}, ISSN={["1463-9084"]}, url={https://doi.org/10.1039/D2CP02437C}, DOI={10.1039/d2cp02437c}, abstractNote={Interaction of a multi-element laser produced plasma with air leads to formation of fractal agglomerates of nanoparticles consisting of multiple elements and their oxides.}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Kautz, Elizabeth J. and Zelenyuk, Alla and Gwalani, Bharat and Phillips, Mark C. and Harilal, Sivanandan S.}, year={2022}, month={Oct} }
 @article{garg_grewal_sharma_gwalani_arora_2022, title={High Oxidation Resistance of AlCoCrFeNi High Entropy Alloy through Severe Shear Deformation Processing}, volume={917}, DOI={10.1016/j.jallcom.2022.165385}, abstractNote={In the current study, the high temperature oxidation behavior of AlCoCrFeNi high entropy alloy (HEA) following severe shear deformation was investigated. X-ray diffraction and transmission electron microscopy analysis confirmed spinodal distribution of B2 and BCC phase in the as cast specimen. In contrast, the processed specimen showed a dual phase microstructure (B2/BCC+FCC) after shear deformation. Electron backscattered diffraction analysis revealed significant grain refinement from 90 µm for the as-cast HEA to nearly 2 µm for the processed specimen. The processed specimen showed up to 66% reduction in the oxidation kinetics compared to the as cast alloy. The remarkable improvement in the high-temperature oxidation performance following processing is attributed to complete microstructure refinement. The current study provides a sustainable solution and a new pathway for addressing the looming problem of material deterioration at high temperatures.}, journal={Journal of Alloys and Compounds}, author={Garg, Mayank and Grewal, Harpreet S. and Sharma, Ram K. and Gwalani, Bharat and Arora, Harpreet S.}, year={2022}, month={Oct}, pages={165385} }
 @article{lan_kovacs_caron_du_song_dasari_gwalani_chaudhary_ramanujan_banerjee_et al._2022, title={Highly complex magnetic behavior resulting from hierarchical phase separation in AlCo (Cr) FeNi high-entropy alloys}, volume={25}, DOI={10.1016/j.isci.2022.104047}, abstractNote={Magnetic high-entropy alloys (HEAs) are a new category of high-performance magnetic materials, with multicomponent concentrated compositions and complex multi-phase structures. Although there have been numerous reports of their interesting magnetic properties, there is very limited understanding about the interplay between their hierarchical multi-phase structures and the resulting magnetic behavior. We reveal for the first time the influence of a hierarchically decomposed B2 + A2 structure in an AlCo0.5Cr0.5FeNi HEA on the formation of magnetic vortex states within individual A2 (disordered BCC) precipitates, which are distributed in an ordered B2 matrix that is weakly ferromagnetic. Non-magnetic or weakly ferromagnetic B2 precipitates in large magnetic domains of the A2 phase, and strongly magnetic Fe-Co-rich interphase A2 regions, are also observed. These results provide important insight into the origin of coercivity in this HEA, which can be attributed to a complex magnetization process that includes the successive reversal of magnetic vortices.}, number={4}, journal={Iscience}, author={Lan, Qianqian and Kovacs, Andras and Caron, Jan and Du, Hongchu and Song, Dongsheng and Dasari, Sriswaroop and Gwalani, Bharat and Chaudhary, Varun and Ramanujan, Raju V. and Banerjee, Rajarshi and et al.}, year={2022}, month={Apr}, pages={104047} }
 @article{yu_ross_johnson_jasthi_gwalani_2022, title={In situ observations of grain growth and recovery in cold sprayed Ni-Y(2)O(3 )and CP-Ni coatings using hot-stage TEM}, volume={192}, ISSN={["1873-4189"]}, DOI={10.1016/j.matchar.2022.112199}, abstractNote={Cold spray is a severe plastic deformation-based processing technique. The material undergoes extreme environments and a large energy can be assumed to be stored in material in form of strain, dislocations, and vacancies. The thermal stability and structural integrity of cermet coatings processed by cold spray for elevated temperature applications are rather important but not well understood. Here, commercially pure-Ni (CP-Ni) and Ni-Y 2 O 3 cermet coatings were fabricated and annealed by an in-situ hot-stage transmission electron microscopy (TEM) technique to investigate and compare the microstructural evolution of these two materials including strain relaxation, sub grain boundary and grain boundary motion which as otherwise impossible to probe using ex situ annealing. The as-deposited CP-Ni exhibits crystallized ultra-fine grains (UFG), while the Ni-Y 2 O 3 coatings show a combination of nanocrystalline (NC) and UFG grains and a non-uniform distribution of Y 2 O 3 in the Ni matrix. The hot-stage TEM results show a decreased strain contrast and limited grain growth for both materials annealed at 350 °C for 2 h. When the materials are continuously heated from 25 °C to 800 °C in 19 min, the presence of nano Y 2 O 3 particles shows pinning effects at grain boundaries, resulting in improved thermal stability of Ni-Y 2 O 3 coatings compared with CP-Ni coatings. • The as-deposited cold sprayed CP-Ni exhibits crystallized ultra-fine grains (UFG). • Ni-Y 2 O 3 coatings show a combination of nanocrystalline and UFG grains and a non-uniform distribution of Y 2 O 3 in the Ni matrix. • Grain growth in the two-dimensional specimen is more sluggish compared to that in the three-dimensional specimen. • Nano Y 2 O 3 addition shows pinning effects at grain boundaries, resulting in improved thermal stability of Ni-Y 2 O 3 coatings.}, journal={MATERIALS CHARACTERIZATION}, author={Yu, Anqi and Ross, Kenneth and Johnson, Kyle and Jasthi, Bharat K. and Gwalani, Bharat}, year={2022}, month={Oct} }
 @article{das_gwalani_ma_upadhyay_2022, title={Metallurgical joining of immiscible system: Pure Mg and pure Fe}, volume={187}, DOI={10.1016/j.matchar.2022.111821}, abstractNote={Understanding the metallurgical joinability of pure Mg and pure Fe and their interfacial microstructure lays the foundation for deciphering the complicated mechanism of joining various magnesium alloys and steels in applications. Pure Mg and pure Fe were successfully joined to form a metallurgical bond for the first time using the friction stir assisted scribe technique. Through detailed characterization, we found that the two immiscible metals are bonded by a critical interfacial oxide layer that spans only ~40 ± 10 nm. We present the first direct experimental evidence of the presence of an Mg/Fe oxide-rich interfacial layer using high-resolution electron microscopy and discuss the contribution of oxide formation toward a successful joining mechanism.}, journal={Materials Characterization}, author={Das, Hrishikesh and Gwalani, Bharat and Ma, Xiaolong and Upadhyay, Piyush}, year={2022}, month={May}, pages={111821} }
 @article{blanc_choi_shyamsunder_key_lapidus_li_yin_li_gwalani_xiao_et al._2022, title={Phase Stability and Kinetics of Topotactic Dual Ca2+-Na+ Ion Electrochemistry in NaSICON NaV2(PO4)3}, volume={12}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.2c02816}, DOI={10.1021/acs.chemmater.2c02816}, abstractNote={: Recent reports of reversible calcium plating and stripping have rekindled interest in the development of Ca-ion batteries (CIBs) as next-generation energy storage devices. This technology has the potential to overcome the limitations of conventional Li-ion batteries, but CIBs are plagued by a paucity of suitable cathode materials. To date, NaSICON-structured NaV 2 (PO 4 ) 3 has been demonstrated as a successful cathode candidate, exhibiting reversible (de)intercalation of 0.6 mol Ca 2+ along with stable cycling performance. However, a complex multiphase mixture forms on discharge so the Ca-ion charge storage mechanism in the NaSICON framework is poorly understood. In this work, we report on an investigation of the structure and/or Na + /Ca 2+ environment(s) of a variety of chemically prepared NaSICON Ca x Na y V 2 (PO 4 ) 3 phases which were characterized using synchrotron XRD, SEM-EDS, 23 Na NMR, and TEM. Highly calciated CaV 2 (PO 4 ) 3 , Ca 1.5 V 2 (PO 4 ) 3 , and CaNaV 2 (PO 4 ) 3 phases can be prepared at high temperature, but � unlike Ca 0.6 NaV 2 (PO 4 ) 3 � these materials are electrochemically inactive. To better understand the fundamental factors impacting successful Ca 2+ electrochemistry in this system, DFT was employed to examine the Ca x Na y V 2 (PO 4 ) 3 phase diagram and Ca 2+ diffusion mechanism. Theoretical insights show that phase separation into Na-rich and Ca-rich phases is a reason for the capacity limitation and demonstrate that Na + ions in the host materials assist the migration of neighboring Ca 2+ ions, enabling reversible electrochemistry in Ca x Na y V 2 (PO 4 ) 3 . This investigation of fundamental principles affecting reversible Ca 2+ (de)intercalation in Ca x Na y V 2 (PO 4 ) 3 allows for the development of design principles to enable the discovery of a variety of successful cathodes for CIBs.}, journal={CHEMISTRY OF MATERIALS}, author={Blanc, Lauren E. and Choi, Yunyeong and Shyamsunder, Abhinandan and Key, Baris and Lapidus, Saul H. and Li, Chang and Yin, Liang and Li, Xiang and Gwalani, Bharat and Xiao, Yihan and et al.}, year={2022}, month={Dec} }
 @article{gwalani_liu_lambeets_olszta_poplawsky_shyam_devaraj_2022, title={Rapid assessment of interfacial stabilization mechanisms of metastable precipitates to accelerate high-temperature Al-alloy development}, volume={10}, DOI={10.1080/21663831.2022.2102947}, abstractNote={Precipitate strengthened high-temperature alloys are currently used in safety-critical applications. Understanding precipitate stability and solute segregation mechanisms at high temperatures is key to designing high-strength alloys. Rapid in-situ approaches, therefore, are pivotal in accelerating the alloy design process. Hereby using the test case of a promising high-temperature Al-Cu-Mn-Zr alloy, we demonstrate the value of in-situ atom probe tomography coupled with in-situ transmission electron microscopy to reveal atomic-scale mechanisms that lead to the emergence of non-equilibrium solute segregation. Mn and Zr segregation at strengthening precipitate(θ’)-matrix interface increases the kinetic barrier for phase transformation thus retaining high-temperature strength. GRAPHICAL ABSTRACT IMPACT STATEMENT Our rapid approach can essentially eliminate lengthy heat treatments, metallographic preparations, and ex-situ characterization steps and thus help accelerate the process of high-temperature alloy design.}, number={12}, journal={Materials Research Letters}, author={Gwalani, Bharat and Liu, Jia and Lambeets, Sten and Olszta, Matthew and Poplawsky, Jonathan and Shyam, Amit and Devaraj, Arun}, year={2022}, pages={771–779} }
 @article{li_powell_mathaudhu_gwalani_devaraj_wang_2022, title={Review of recent progress on in situ TEM shear deformation: a retrospective and perspective view}, volume={57}, DOI={10.1007/s10853-022-07331-4}, journal={Journal of Materials Science}, author={Li, S. and Powell, C.A. and Mathaudhu, S. and Gwalani, B. and Devaraj, A. and Wang, C.}, year={2022}, pages={12177–12201} }
 @article{ma_gwalani_tao_efe_olszta_song_yadav_yu_nizolek_carpenter_et al._2022, title={Shear strain gradient in Cu/Nb nanolaminates: Strain accommodation and chemical mixing}, url={https://doi.org/10.1016/j.actamat.2022.117986}, DOI={10.1016/j.actamat.2022.117986}, abstractNote={Disentangling the intragranular and interfacial plasticity contribution to the overall strain accommodation is crucial to understanding the microstructural evolution and mass transport upon deformation in materials with the nanoscale feature size. Here, we devise a new approach to tackle the issue by introducing shear strain gradients into Cu/Nb nanolaminates of different layer thicknesses with the shear perpendicular to the laminate interfaces. The measurement of the strain gradient and the resultant lattice disorientation enables a quantitative understanding of the intragranular and interfacial plasticity contribution. We found that intragranular slip entirely governs the deformation in the 300 nm-layer laminate and, unexpectedly, contributes ∼80% of the total plasticity in the 30 nm-layer laminate. The high intragranular plasticity in the thin laminate is attributed to the large width of confined slip planes and their remnant potential for storing dislocations. In addition, substantial forced chemical mixing is observed in the top region of the 30 nm-layer laminate where the effective layer thickness is reduced below 8 nm. The transition of deformation mechanism from confined layer slip to dislocation transmission is largely responsible for the initiation of substantial mixing. Our method and findings shed light on the deformation mechanism and deformation-induced mass transport behavior in nanostructured materials.}, journal={Acta Materialia}, author={Ma, Xiaolong and Gwalani, Bharat and Tao, Jinhui and Efe, Mert and Olszta, Matthew and Song, Miao and Yadav, Sakshi and Yu, Anqi and Nizolek, Thomas J. and Carpenter, John S. and et al.}, year={2022}, month={Aug} }
 @book{reza-e-rabby_srivastava_pole_nittala_gwalani_kappagantula_2022, title={Solid Phase Processing of Lead-Free Brass with Carbon Additives}, url={https://doi.org/10.2172/1983976}, DOI={10.2172/1983976}, abstractNote={Currently, “lead-free” brass alloys (like C27450/C27451/C6930), used extensively in drinking water fixtures and automotive, electrical, and electronic applications contain maximum 0.25% lead to maintain mechanical performance and machinability. Adding graphite to brass as an alternative to lead, using casting, powder metallurgy, and extrusion methods, has been explored previously. However, all these methods have proven to be energy-, time-, and resource-intensive, while not enabling performance equivalent to that of C36000 brass. In this project, we developed a one-step approach using friction extrusion and ShAPE to make lead-free brass/graphite components such as wires, rods and tubes with mechanical performance equivalent to commercial lead-free brass alloys. Manufacturing temperatures were maintained ~550-730 °C with feed rates ranging between 4 – 25 mm/min. Results show larger grains at the center of the rods and wires with smaller grains developing at the edges. Graphite particles were sheared in the direction of extrusion with higher strains observed towards the edges. Hardness of the brass/graphite samples was over 25% higher than that of the corresponding brass-only samples (rods and wires), also friction extruded. Our results show that the sub-micron graphite plays an important role in limiting process temperature and restraining grain growth during friction extrusion, thus reducing grain size in composites.}, author={Reza-E-Rabby, Md. and Srivastava, Abhinav and Pole, Mayur and Nittala, Aditya and Gwalani, Bharat and Kappagantula, Keerti}, year={2022}, month={Sep} }
 @article{ma_olszta_liu_song_pole_pallaka_silverstein_escobar_bhattacharjee_mukherjee_et al._2022, title={Temperature-dependent formation of gradient structures with anomalous hardening in an Al-Si alloy}, volume={858}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2022.144061}, abstractNote={The temperature effect on forming gradient structure in an Al–Si alloy during surface severe deformation is studied in this report. The intermediate temperature (473 K) produces the steepest gradient structure by an anomalous hardening on the top layer compared to lower (300 K) and higher temperature (673 K) counterparts. Our analysis shows profuse aluminum oxide particles in the top layer of the gradient structure under 473 K lead to anomalous hardening by oxide-dispersion strengthening. The counterintuitive enhancement of strengthening at the intermediate temperature is explained by the dynamic interplay between thermal-driven, mechanical-aided oxidation and the wear-induced loss of surface materials as a function of temperature, which yields a critical processing temperature to achieve the steepest gradient structure.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Ma, Xiaolong and Olszta, Matthew and Liu, Jia and Song, Miao and Pole, Mayur and Pallaka, Madhusudhan R. and Silverstein, Joshua and Escobar, Julian and Bhattacharjee, Arun J. and Mukherjee, Sundeep and et al.}, year={2022}, month={Nov} }
 @article{gwalani_song_silverstein_escobar_wang_pole_johnson_jasthi_devaraj_ross_2022, title={Thermal stability and mechanical properties of cold-sprayed Nickel-Yttria coating}, url={https://doi.org/10.1016/j.scriptamat.2021.114281}, DOI={10.1016/j.scriptamat.2021.114281}, abstractNote={The microstructural evolution under the extreme environments imposed during cold spray deposition and the microstructural recovery during post-processing annealing treatments is rather complex and not well understood. Here, Nickel-Yttria (Ni-Y2O3) cermet coatings on a 304 stainless steel (SS304) substrate were produced using cold spray technique, resulting in a bimodal grain structure. The phase stability, mechanical properties are investigated in both as-deposited and annealed (350 ⁰C) Ni-Y2O3 coatings. A multimodal microstructural characterization using electron microscopy, and atom probe tomography shows the structural and compositional stability of Y2O3 particles and Ni grains. A fragmentation of Y-rich particles and dispersion in Ni was observed, however, no forced mixing/dissolution of Y in Ni is detected. As compared with pure Ni coating (control test), Ni-Y2O3 coating slowed a retarded grain growth during annealing. Additionally, Ni-Y2O3 coating was 1.5 times harder and showed better thermal and mechanical stability compared to the Ni coating after annealing.}, journal={Scripta Materialia}, author={Gwalani, Bharat and Song, Miao and Silverstein, Joshua and Escobar, Julian and Wang, Tianhao and Pole, Mayur and Johnson, Kyle and Jasthi, Bharat K and Devaraj, Arun and Ross, Kenneth}, year={2022}, month={Jan} }
 @article{wang_shukla_gwalani_sinha_thapliyal_frank_mishra_2021, title={Co-introduction of precipitate hardening and TRIP in a TWIP high-entropy alloy using friction stir alloying}, volume={11}, DOI={10.1038/s41598-021-81350-0}, abstractNote={Abstract}, journal={Scientific reports}, author={Wang, Tianhao and Shukla, Shivakant and Gwalani, Bharat and Sinha, Subhasis and Thapliyal, Saket and Frank, Michael and Mishra, Rajiv S.}, year={2021}, pages={1579} }
 @book{ross_pole_gwalani_montoya_karasz_schaller_2021, title={Cold Spray for Mitigation and Repair of Spent Nuclear Fuel Dry Storage Canisters}, url={https://doi.org/10.2172/1880046}, DOI={10.2172/1880046}, abstractNote={The purpose of this work is to investigate the use of cold spray for repair and mitigation of chloride-induced stress corrosion cracking (CISCC) in dry cask storage system (DCSS) canisters to ensure their integrity far beyond their original license period. This report provides a viability analysis of cold spray for repair and mitigation of CISCC in DCSS canisters to extend canister life.}, author={Ross, Kenneth and Pole, Mayur and Gwalani, Bharat and Montoya, Timothy and Karasz, Erin and Schaller, Rebecca}, year={2021}, month={Sep} }
 @article{dasari_chang_jagetia_vishal soni_gwalani_gorsse_yeh_banerjee_2021, title={Discontinuous precipitation leading to nano-rod intermetallic precipitates in an Al0.2Ti0.3Co1.5CrFeNi1.5 high entropy alloy results in an excellent strength-ductility combination}, volume={805}, journal={Materials Science and Engineering: A}, author={Dasari, Sriswaroop Y.-J.Chang and Chang, Y.J. and Jagetia, Abhinav and Vishal Soni, A.Sharma and Gwalani, Bharat and Gorsse, Stéphane and Yeh, A.-C. and Banerjee, Rajarshi}, year={2021}, month={Feb}, pages={140551} }
 @book{gwalani_pole_whalen_li_o'callahan_tao_nittala_kappagantula_2021, title={Evaluating Effects of Shear Processing on 2D Crystalline Materials in 3D Metal Matrices: Atomistic Understanding of High Shear Deformation of Copper Graphene Composites}, url={https://doi.org/10.2172/1985708}, DOI={10.2172/1985708}, abstractNote={Composites made of copper and graphene demonstrate high strength, lubricity and enhanced electrical and thermal conductivity compared pure copper. However, manufacturing these composites at bulk volumes for industrial applications has been a big challenge. Shear deformation assisted processing is an effective method for manufacturing materials such as copper-graphene composites demonstrating ultra-fine grain structures and compositional homogeneity. Nevertheless, microstructural evolution of the composites and their property development under such conditions is not clearly understood currently. To rectify this gap in literature, high strain shear deformation of copper coated graphene foils was performed using a tribometer pin in this study. Changes in microstructure of the composite as well as the constituent components under shear deformation was correlated to process conditions. A sharp increase in the coefficient of friction attributed to rupture and smearing of graphene layer into copper substrate was observed during the shear processing. The coefficient of friction of the sheared copper/graphene composite was lower than that of pure copper, suggesting that partially worn graphene is effectively lubricious at the macroscale. A multimodal characterization of the processed region further revealed a shear deformation-induced ultrafine two-phase grain-structure consisting of copper and graphitic domains. Shear deformation reduced the copper grain size from around 50 – 100 µm to ~200 nm on an average and ~2 – 5 nm in some locations. The semicrystalline graphene films were observed to fracture into 10 – 50 µm size flakes. Oxygen enrichment was observed in the processed region. Finally, graphitic domain were identified for the first time in the copper matrix and not just at the grain boundaries providing evidence for a metastable composite microstructure as a result of solid phase processing at room temperature.}, author={Gwalani, Bharat and Pole, Mayur and Whalen, Kate and Li, Shuang and O'Callahan, Brian and Tao, Jinhui and Nittala, Aditya and Kappagantula, Keerti}, year={2021}, month={Sep} }
 @article{srimark_dasari_sharma_wangyao_gwalani_rojhirunsakool_gorsse_banerjee_2021, title={Hierarchical phase evolution in a lamellar Al0. 7CoCrFeNi high entropy alloy involving competing metastable and stable phases}, volume={204}, DOI={10.1016/j.scriptamat.2021.114137}, abstractNote={Guided by solution thermodynamic modeling coupled with detailed experimental characterization, the present study establishes that the alternating FCC and BCC lamellar microstructure in the Al0.7CoCrFeNi high entropy alloy, is a result of non-equilibrium partitionless solidification from the liquid to single B2 phase, followed by solid-state decomposition. Widmanstätten FCC lamellae form from the allotriomorphic FCC precipitates at the B2 grain boundaries, leading to a lamellar microstructure, divided into two distinct sub-systems. Isothermal annealing further drives these individual sub-systems towards equilibrium via precipitation of ordered intermetallic phases. The transformation in FCC lamellae initiates by the formation of metastable L12 precipitates at shorter annealing times, which are eventually replaced by the equilibrium BCC and B2 phases, forming composite B2+BCC laths, on long term annealing. These results further exemplify that interesting transformation pathways lead to hierarchical microstructures within HEAs, and the fact that as processed conditions in these alloys are often far-from equilibrium.}, journal={Scripta Materialia}, author={Srimark, K. and Dasari, S. and Sharma, A. and Wangyao, P. and Gwalani, B. and Rojhirunsakool, T. and Gorsse, S. and Banerjee, R.}, year={2021}, month={Nov}, pages={114137} }
 @article{gwalani_dasari_sharma_soni_shukla_jagetia_agrawal_mishra_banerjee_2021, title={High density of strong yet deformable intermetallic nanorods leads to an excellent room temperature strength-ductility combination in a high entropy alloy}, volume={219}, DOI={10.1016/j.actamat.2021.117234}, abstractNote={This paper introduces a new microstructural template for high entropy alloys (HEAs), where the face centered cubic (FCC) complex concentrated solid solution is reinforced with a high density of strong, yet deformable, nanorods of an ordered multi-component intermetallic L12 compound. Thermodynamic modeling has been employed to design this HEA with a large L12 volume fraction. Thermo-mechanical processing by isothermal annealing of the conventionally processed bulk cold-rolled alloy directly at precipitation temperatures, has been applied to produce a high density of uniformly distributed L12 nanorods within refined FCC grains, resulting from concomitant recrystallization and discontinuous precipitation processes. The nanorod morphology of the discontinuous L12 product has been established from three-dimensional atom probe tomography. The refined grains result in a complete coverage of the microstructure with discontinuously precipitated intermetallic nanorods. This nanorod strengthened HEA exhibits an exceptionally high room temperature yield strength of ∼1630 MPa, good tensile ductility of ∼15%, and an ultimate tensile strength of ∼1720 MPa. Furthermore, a single L12 phase alloy, melted based on the precipitate composition in the two-phase FCC + L12 HEA, exhibits very high compressive deformability and strain hardenability, unusual for ordered intermetallic compounds. These results open a new strategy for design of fine-grained microstructures strengthened via ordered intermetallic phases, exploiting the beneficial effects of discontinuous precipitation, for achieving very high room temperature tensile strengths while maintaining good ductility.}, journal={Acta Materialia}, author={Gwalani, Bharat and Dasari, Sriswaroop and Sharma, Abhishek and Soni, Vishal and Shukla, Shivakant and Jagetia, Abhinav and Agrawal, Priyanshi and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2021}, month={Oct}, pages={117234} }
 @book{lan_kovacs_caron_du_song_dasari_gwalani_chaudhary_ramanujan_banerjee_et al._2021, title={Highly Complex Magnetic Structures Resulting From Hierarchical Phase Separation in AlCo (Cr) FeNi High Entropy Alloys}, DOI={10.48550/arXiv.2104.00943}, abstractNote={Magnetic high entropy alloys (HEAs) are a new category of high-performance magnetic materials, with multi-component concentrated compositions and complex multi-phase structures. Although there have been numerous reports of their interesting magnetic properties, there is very limited understanding about the interplay between their hierarchical multi-phase structures and their local magnetic structures. By employing high spatial resolution correlative magnetic, structural and chemical studies, we reveal the influence of a hierarchically decomposed B2 + A2 structure in an AlCo0.5Cr0.5FeNi HEA on the formation of magnetic vortex states within individual A2 (disordered BCC) precipitates, which are distributed in an ordered B2 matrix that is weakly ferromagnetic. Non-magnetic or weakly ferromagnetic B2 precipitates in large magnetic domains of the A2 phase, and strongly magnetic Fe-Co-rich interphase A2 regions, are also observed. These results provide important insight into the origin of coercivity in this HEA, which can be attributed to a complex magnetization process that includes the successive reversal of magnetic vortices.}, number={2104.009432104.00943}, author={Lan, Qianqian and Kovacs, Andras and Caron, Jan and Du, Hongchu and Song, Dongsheng and Dasari, Sriswaroop and Gwalani, Bharat and Chaudhary, Varun and Ramanujan, Raju V. and Banerjee, Rajarshi and et al.}, year={2021} }
 @article{özdogru_cha_gwalani_murugesan_song_çapraz_2021, title={In Situ Probing Potassium-Ion Intercalation-Induced Amorphization in Crystalline Iron Phosphate Cathode Materials}, volume={21}, DOI={10.1021/acs.nanolett.1c02095}, abstractNote={Na-ion and K-ion batteries are promising alternatives for large-scale energy storage due to their abundance and low cost. Intercalation of these large ions could cause irreversible structural deformation and partial to complete amorphization in the crystalline electrodes. A lack of understanding of the dynamic changes in the amorphous nanostructure during battery operation is the bottleneck for further developments. Here, we report the utilization of in-operando digital image correlation and XRD techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium ion intercalation. In-operando XRD demonstrates amorphization in the electrode's nanostructure during the first charge and discharge cycle. Additionally, ex situ HR-TEM further confirms the amorphization after potassium-ion intercalation. An in situ strain analysis detects reversible deformations associated with redox reactions in the amorphous phases. Our approach offers new insights into the mechanism of ion intercalation in the amorphous nanostructure which are highly potent for the development of next-generation batteries.}, number={18}, journal={Nano Letters}, author={Özdogru, Bertan and Cha, Younghwan and Gwalani, Bharat and Murugesan, Vijayakumar and Song, Min-Kyu and Çapraz, Ömer Özgür}, year={2021}, pages={7579–7586} }
 @article{li_olszta_li_gwalani_soulami_powell_mathaudhu_devaraj_wang_2021, title={In-situ TEM observation of shear induced microstructure evolution in Cu-Nb alloy}, volume={205}, url={http://dx.doi.org/10.1016/j.scriptamat.2021.114214}, DOI={10.1016/j.scriptamat.2021.114214}, abstractNote={Phase boundaries in multiphase alloys govern defect interaction and chemical intermixing across different phases during plastic deformation. Dynamic interaction of defects with phase boundaries in multiphase alloys, especially for immiscible alloys, has generated more research interest in recent years. Here, we describe a novel approach for carrying out in-situ TEM shear deformation to directly observe interfacial microstructural evolution of a Cu-Nb alloy. A unique double shear specimen geometry is microfabricated by a focused ion beam technique to apply shear deformation upon push loading inside the TEM. From the real-time observation, we discover that the phase boundary with a zigzag morphology effectively blocks stacking faults nucleated in a Cu grain from slipping into a Nb grain. Meanwhile, the Cu phase bears the most plastic deformation through slip or twinning mechanisms. This work sheds light on understanding the shear deformation and the behavior of phase boundaries in multiphase alloys during shear deformation.}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Li, Shuang and Olszta, Matthew and Li, Lei and Gwalani, Bharat and Soulami, Ayoub and Powell, Cynthia A. and Mathaudhu, Suveen and Devaraj, Arun and Wang, Chongmin}, year={2021}, month={Dec}, pages={114214} }
 @article{gwalani_torgerson_dasari_jagetia_nartu_gangireddy_pole_tianhao wang_banerjee_2021, title={Influence of fine-scale B2 precipitation on dynamic compression and wear properties in hypo-eutectic Al0. 5CoCrFeNi high-entropy alloy}, volume={853}, DOI={10.1016/j.jallcom.2020.157126}, abstractNote={The near equi-atomic high-entropy alloys based on Al, Co, Cr, Fe, Ni have provided a novel microstructural template for alloy design. The face centered cubic (FCC) matrix strengthened by body centered cubic (BCC) based ordered B2 precipitates can be used to develop new generation of precipitation strengthened alloys. The present study focuses on an Al0.5CoCrFeNi hypo-eutectic alloy consisting of an as-solidified FCC + B2 microstructure. Guided by solution thermodynamic modeling, this alloy has been isothermally aged for solid-state precipitation of a high fraction of fine scale intragranular B2 particles. While, the positive influence of B2 on tensile strength, and work hardenability have been published earlier, the current work presents effect of fine scale B2 phase on sliding wear and dynamic compression properties. The flow stress at 0.02% true strain increased from ∼670 MPa to ∼1350 (102%) MPa, the ultimate compressive strength increased from ∼1160 MPa to 1500 MPa (20%), and the wear resistance increased more than 5 times with progressively increasing phase fraction of B2 precipitates.}, journal={Journal of Alloys and Compounds}, author={Gwalani, Bharat and Torgerson, Tyler and Dasari, Sriswaroop and Jagetia, Abhinav and Nartu, M.S.K.K.Y. and Gangireddy, Sindhura and Pole, Mayur and Tianhao Wang, T.W.Scharf and Banerjee, Rajarshi}, year={2021}, month={Feb}, pages={157126} }
 @article{sharma_gwalani_dasari_choudhuri_chang_gorsse_yeh_banerjee_2021, title={Insights into Defect-Mediated Nucleation of Equilibrium B2 Phase in Face-Centered Cubic High-Entropy Alloys}, volume={73}, DOI={10.1007/s11837-021-04754-3}, abstractNote={Though a fine-scale second-phase distribution is a potent strengthening mechanism for alloys, achieving a high precipitate density is often difficult owing to sluggish precipitation kinetics and limited nucleation sites. More specifically, in case of transition-element-based complex concentrated alloys (CCAs) or high-entropy alloys (HEAs), precipitation of the equilibrium strengthening phase, such as the ordered B2 phase, can be limited due to its high nucleation barrier for homogeneous precipitation within the face-centered cubic (FCC) matrix. This can lead to competing homogeneous nucleation of a metastable ordered L12 phase, which has a substantially lower nucleation barrier since it is isostructural with the FCC matrix. Using three different CCAs/HEAs as examples, thermomechanical processing has been employed to introduce a large number density of homogeneously distributed heterogeneous nucleation sites within the FCC matrix, to manipulate the phase fraction, morphology, and distribution of B2 precipitates. This approach of tailoring the microstructure is widely applicable to other multicomponent alloys.}, journal={JOM}, author={Sharma, Abhishek and Gwalani, Bharat and Dasari, Sriswaroop and Choudhuri, Deep and Chang, Yao-Jen and Gorsse, Stephane and Yeh, An-Chou and Banerjee, Rajarshi}, year={2021}, pages={2320–2331} }
 @article{das_upadhyay_wang_gwalani_ma_2021, title={Interfacial reaction during friction stir assisted scribe welding of immiscible Fe and Mg alloy system}, volume={11}, DOI={10.1038/s41598-021-81266-9}, abstractNote={Abstract}, journal={Scientific reports}, author={Das, Hrishikesh and Upadhyay, Piyush and Wang, Tianhao and Gwalani, Bharat and Ma, Xiaolong}, year={2021}, pages={1588} }
 @article{gwalani_fu_olszta_silverstein_yadav_manimunda_guzman_xie_rohatgi_mathaudhu_et al._2021, title={Lattice misorientation evolution and grain refinement in Al-Si alloys under high-strain shear deformation}, volume={18}, url={http://dx.doi.org/10.1016/j.mtla.2021.101146}, DOI={10.1016/j.mtla.2021.101146}, abstractNote={The starting alloy microstructure can be tailored to achieve varying degrees of grain refinement and enhance mechanical properties through severe plastic shear deformation during solid-phase processing. Crystal plasticity-based grain misorientation modeling, coupled with systematic pin-on-disk tribometry-based subsurface shear deformation experiments on as-cast Al-xSi alloys (x = 0, 1, 4 at%), was conducted. The post-deformation microstructural analysis, through a combined computational and experimental approach, conclusively shows that the initial volume fraction of the hard Si phase enhances the evolution of local lattice misorientation, leading to efficient grain refinement during severe plastic shear deformation. The shear-deformation–induced nanostructure resulted in more than double the nanoindentation hardness in the processed alloy.}, journal={Materialia}, publisher={Elsevier BV}, author={Gwalani, Bharat and Fu, Wenkai and Olszta, Mathew and Silverstein, Joshua and Yadav, Digvijay R. and Manimunda, Praveena and Guzman, Anthony and Xie, Kelvin and Rohatgi, Aashish and Mathaudhu, Suveen and et al.}, year={2021}, month={Aug}, pages={101146} }
 @article{kautz_schreiber_devaraj_gwalani_2021, title={Mechanistic insights into selective oxidation and corrosion of multi-principal element alloys from high resolution and in situ microscopy}, volume={18}, url={http://dx.doi.org/10.1016/j.mtla.2021.101148}, DOI={10.1016/j.mtla.2021.101148}, abstractNote={Multiple principal element alloys (MPEAs) have drawn significant recent interest from the metallurgical research community. These novel alloys have the potential to replace traditional alloys with a range of tailored mechanical properties, corrosion resistance, and radiation tolerance enabled by complex compositions. The broad alloy design space of MPEAs presents a great opportunity to discover new forms of oxidation and corrosion resistance in extreme environments that break away from conventional alloy design criteria. However, understanding the oxidation and corrosion response of MPEAs can be a challenging task due the complex compositional, structural, and chemical state changes occurring in the oxide or corrosion film and at its interface with the base alloy. This perspective discusses the utility of high resolution and in situ microscopy techniques for revealing unique aspects of MPEA oxidation and corrosion behavior at the atomic and near atomic scales. Challenges of studying oxidation and corrosion response of these alloys and several open questions are presented.}, journal={Materialia}, publisher={Elsevier BV}, author={Kautz, Elizabeth J. and Schreiber, Daniel K. and Devaraj, Arun and Gwalani, Bharat}, year={2021}, month={Aug}, pages={101148} }
 @article{kaspar_pang_sushko_bowden_tao_gwalani_olszta_efe_devaraj_rohatgi_2021, title={Metastable orientation relationships in thin film Cu-Cr bilayers}, volume={194}, DOI={10.1016/j.scriptamat.2020.113635}, abstractNote={Metastable orientation relationships (ORs) between Cu and Cr are stabilized via epitaxial thin film deposition, with the initial layer of Cu(001) or Cr(001) grown epitaxially on MgO(001). The Bain OR is observed by x-ray diffraction and scanning/transmission electron microscopy for Cu(001) / Cr(001). In contrast, three Cr/Cu ORs are found for Cr deposition on Cu(001): the Pitsch OR, and two previously unreported ORs related to the Bain and Pitsch ORs, respectively. Ab initio calculations predict the energetics of these metastable ORs, and reveal that the deformation resistance of Cr makes the Bain OR energetically unfavorable when Cr films are deposited on Cu(001). These results show that kinetic constraints imposed by controlling the substrate surface and deposition conditions can lead to metastable interfacial structures.}, journal={Scripta Materialia}, author={Kaspar, Tiffany C. and Pang, Qin and Sushko, Peter V. and Bowden, Mark E. and Tao, Jinhui and Gwalani, Bharat and Olszta, Matt and Efe, Mert and Devaraj, Arun and Rohatgi, Aashish}, year={2021}, month={Mar}, pages={113635} }
 @article{oleksak_addou_gwalani_baltrus_liu_diulus_devaraj_herman_doğan_2021, title={Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2}, url={https://doi.org/10.1038/s41529-021-00194-1}, DOI={10.1038/s41529-021-00194-1}, abstractNote={Abstract}, journal={npj Materials Degradation}, author={Oleksak, Richard P. and Addou, Rafik and Gwalani, Bharat and Baltrus, John P. and Liu, Tao and Diulus, J. Trey and Devaraj, Arun and Herman, Gregory S. and Doğan, Ömer N.}, year={2021}, month={Sep} }
 @article{escobar_gwalani_olszta_silverstein_overman_bergmann_dos santos_staron_maawad_klusemann_et al._2021, title={Multimodal analysis of spatially heterogeneous microstructural refinement and softening mechanisms in three-pass friction stir processed Al-4Si alloy}, volume={887}, DOI={10.1016/j.jallcom.2021.161351}, abstractNote={Solid phase processing methods such as friction stir processing (FSP) offer pathways to refine the microstructure of metallic alloys through the combined action of deformation and deformation-induced heating. However, this thermomechanical coupling during FSP also leads to the occurrence of multiple competing microstructural evolution mechanisms which in turn can lead to locally varying mechanical properties, often distributed heterogeneously in the microstructure. This inherent microstructural and mechanical property heterogeneity in alloys subjected to FSP makes it rather challenging to reveal the microstructure-mechanical property relationships systematically. Therefore in this work, we systematically analyze the relationship between microstructural evolution and local microhardness in a model binary Al-4 at.% Si alloy subjected to three-pass friction stir processing. Spatially resolved high-energy synchrotron X-ray diffraction, electron backscattered diffraction, and scanning transmission electron microscopy were used to understand the heterogeneous microstructural evolution due to the FSP. Our results provide insight into how particle-stimulated grain nucleation, recovery, and recrystallization occur heterogeneously in the Al-Si alloy as a function of the distance from the stir zone, directly influencing the degree of softening. The systematic understanding developed by this work can guide future studies on the influence of FSP process parameters on the microstructural evolution mechanisms and its influence on local mechanical properties}, journal={Journal of Alloys and Compounds}, author={Escobar, Julian and Gwalani, Bharat and Olszta, Matthew and Silverstein, Joshua and Overman, Nicole and Bergmann, Luciano and dos Santos, Jorge F. and Staron, Peter and Maawad, Emad and Klusemann, Benjamin and et al.}, year={2021}, month={Dec}, pages={161351} }
 @article{efe_gwalani_tao_song_kaspar_devaraj_rohatgi_2021, title={Nanomechanical scratching induced local shear deformation and microstructural evolution in single crystal copper}, volume={562}, url={http://dx.doi.org/10.1016/j.apsusc.2021.150132}, DOI={10.1016/j.apsusc.2021.150132}, abstractNote={Shear deformation at the nanoscale has practical applications due to the ability of shear strains to significantly change the microstructures and textures of the deforming materials, and for material removal processes at this scale. Here we demonstrate nanomechanical scratching with atomic force microscopy (AFM) as a tool to impose large shear strains on nanoscale material volumes in single-crystal copper. Nano-scratching, with the process parameters and AFM tip geometry used here, resulted in material removal through the cutting mode. This mode enabled the use of stress and strain models, developed for bulk machining, to be applied for AFM cutting as well. The models for bulk-scale were used to predict the strains in the chip (γ ≈ 3.9) and in the surface (γ ≈ 4.6) and the depth of deformed subsurface. Detailed characterization of the scratch region with transmission electron microscopy (TEM) showed microstructural refinement comprising 0.2 μm wide dislocation cells in the chips that resemble features during shear deformation of copper single-crystals at bulk-scale. The subsurface also contained dislocation networks and stacking faults up to ~1.1 μm depth. These results highlight the unique ability of AFM for imparting local shear deformation in materials and studying its effects on the microstructure.}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Efe, Mert and Gwalani, Bharat and Tao, Jinhui and Song, Miao and Kaspar, Tiffany C. and Devaraj, Arun and Rohatgi, Aashish}, year={2021}, month={Oct}, pages={150132} }
 @article{jagetia_nartu_dasari_sharma_gwalani_banerjee_2021, title={Ordering-mediated local nano-clustering results in unusually large Hall-Petch strengthening coefficients in high entropy alloys}, volume={9}, DOI={10.1080/21663831.2020.1871440}, abstractNote={This paper reports a dramatic increase in the grain boundary strengthening or Hall-Petch coefficient, K, by systematically investigating the effect of Al addition on tensile yield strength in CoFeNi and CoCrFeNi high entropy alloys (HEAs) or complex concentrated alloys (CCAs). Additionally, detailed atom probe tomography (APT) revealed a high number density of Ni-Al rich nano-clusters in the Al0.3CoFeNi and Al0.3CoCrFeNi HEAs/CCAs, which can be rationalized based on the strong chemical ordering tendency between these elements. Consequently, the huge increase in K value can be attributed to the additional stress required for overcoming coherency strain fields arising from these nano-clusters. GRAPHICAL ABSTRACT IMPACT STATEMENT This paper reports that the Hall-Petch co-efficient (K) dramatically increase when Al is added to CoFeNi/CoCrFeNi alloys. Such a trend is attributed to the ordering mediated nano-clustering in Al containing HEA/CCAs.}, number={5}, journal={Materials Research Letters}, author={Jagetia, A. and Nartu, M.S.K.K.Y. and Dasari, S. and Sharma, A. and Gwalani, B. and Banerjee, R.}, year={2021}, pages={213–222} }
 @article{liu_olszta_gwalani_park_mathaudhu_devaraj_2021, title={Phase transformations, microstructural refinement and defect evolution mechanisms in Al-Si alloys under non-hydrostatic diamond anvil cell compression}, volume={15}, journal={Materialia}, author={Liu, Tingkun and Olszta, Matthew and Gwalani, Bharat and Park, Changyong and Mathaudhu, Suveen and Devaraj, Arun}, year={2021}, month={Mar}, pages={101049} }
 @article{dasari_sarkar_sharma_gwalani_choudhuri_soni_manda_samajdar_banerjee_2021, title={Recovery of cold-worked Al0. 3CoCrFeNi complex concentrated alloy through twinning assisted B2 precipitation}, volume={202}, DOI={10.1016/j.actamat.2020.10.071}, abstractNote={While the theory of recovery and recrystallization processes during annealing of pure metals and simple alloys is relatively well charted, systematic investigation of these processes in high entropy alloys or complex concentrated alloys (HEA/CCAs) is rather limited. The present paper focuses on the complex interplay between traditional recovery via dislocation annihilation, formation of annealing twins, and precipitation processes during isothermal annealing of a cold-worked candidate Al0.3CoCrFeNi HEA/CCA. While the cold-worked alloy contained a large number density of deformation twins, subsequent isothermal annealing resulted in a further increase in the fraction of Σ3 twin boundaries, which in turn acted as heterogeneous nucleation sites for ordered B2 precipitates. The heterogeneous microstructure obtained after isothermal annealing consists of coarse non-recrystallized FCC grains with high lattice curvature, and uniform distribution of B2 precipitates at prior grain boundaries, deformation bands and twins. The tensile yield stress increased with annealing time and this trend was attributed to the coupled effect of increasing fraction of Σ3 twin boundaries, and ordered B2 precipitates decorating these defects. After long-term annealing at 700°C the alloy exhibits an excellent combination of tensile yield stress ∼1010 MPa and ductility ∼15%, as well as substantial recovery of the strain hardenability.}, journal={Acta Materialia}, author={Dasari, S. and Sarkar, A. and Sharma, A. and Gwalani, B. and Choudhuri, D. and Soni, V. and Manda, S. and Samajdar, I. and Banerjee, R.}, year={2021}, month={Jan}, pages={448–462} }
 @book{wang_li_gwalani_komarasamy_2021, title={Solid Phase Gradient Alloying Method via ShAPE}, url={https://doi.org/10.2172/1988624}, DOI={10.2172/1988624}, author={Wang, Tianhao and Li, Xiao and Gwalani, Bharat and Komarasamy, Mageshwari}, year={2021}, month={Oct} }
 @book{gwalani_song_silverstein_escobar_wang_pole_johnson_jasthi_devaraj_ross_2021, title={Thermal Stability and Mechanical Properties of Cold-Sprayed Ni-Yttria Coating}, DOI={10.2139/ssrn.3897768}, abstractNote={The microstructural evolution under the extreme environments imposed during cold spray deposition of cermet coatings and the microstructural recovery during post-processing annealing treatments is rather complex and not well understood. Here, Ni-Yttria cermet coatings on an SS304 substrate were produced using cold spray technique, resulting in a bimodal grain structure. The grain growth, phase stability, hardness, and wear properties are observed in as-deposited and annealed (at 400 ⁰C) Ni-Yttria and pure Ni coatings. A multimodal microstructural characterization using electron microscopy, and atom probe tomography shows the structural and compositional stability of yttria particles and Ni grains. A fragmentation of Y-rich particles and dispersion in Ni was observed, however, no forced mixing/dissolution of Y in Ni is detected. Nano-yttria dispersed within the Ni grains slowed the grain growth during annealing. After annealing, Yttria reinforced coating was 1.5 times harder and showed better thermal and mechanical stability compared to the Ni coating.}, institution={SSRN}, author={Gwalani, Bharat and Song, Miao and Silverstein, Joshua and Escobar, Julian and Wang, Tianhao and Pole, Mayur and Johnson, Kyle and Jasthi, Bharat K. and Devaraj, Arun and Ross, Kenneth A.}, year={2021} }
 @article{dasari_jagetia_sharma_nartu_soni_gwalani_gorsse_banerjee_2021, title={Tuning the degree of chemical ordering in the solid solution of a complex concentrated alloy and its impact on mechanical properties}, volume={212}, DOI={10.1016/j.actamat.2021.116938}, abstractNote={Using the binary enthalpies of mixing in a Co-Cr-Fe-Ni base alloy system, a high entropy alloy (HEA) or complex concentrated alloy (CCA), the equiatomic CoFeNi has been identified, which should form a random solid solution. Subsequent experimental validation established that this alloy is indeed a near-ideal, random face centered cubic (FCC) solid solution. The same thermodynamic basis has been employed to systematically engineer the degree of chemical ordering within the random CoFeNi alloy, from localized domains of short-range ordering (SRO), also referred to as clustered ordering, to well-defined long-range ordered (LRO) domains, by adding controlled amounts of Al and Ti, since these elements have a strong ordering tendency (negative enthalpy of mixing) with Co, Fe, and Ni. A series of seven alloys were designed in this study, based on enthalpies of mixing among 3d transition metals. This change in the degree of chemical ordering has a strong influence on the tensile yield strength of the alloy, for the same nominal grain size, ranging from ~181 MPa in case of CoFeNi to ~793 MPa in case of the Al0.3Ti0.2Co0.7FeNi1.7 CCA. These experimentally measured yield strengths of the candidate CCAs are in close agreement with predicted values afforded by simple strengthening models.}, journal={Acta Materialia}, author={Dasari, Sriswaroop and Jagetia, A. and Sharma, A. and Nartu, M.S.K.K.Y. and Soni, Vishal and Gwalani, Bharat and Gorsse, Stéphane and Banerjee, Rajarshi}, year={2021}, month={Jun}, pages={116938} }
 @article{gwalani_shukla_leonard_poplawsky_pierce_kovarik_muralidharan_devaraj_2021, title={Understanding the microstructural stability in a γ′-strengthened Ni-Fe-Cr-Al-Ti alloy}, volume={886}, DOI={10.1016/j.jallcom.2021.161207}, abstractNote={Ni-Fe-Cr-Al-Ti alloys, with Ni levels of about 45 at% have the potential to develop a microstructure consisting of a face-centered cubic (γ) matrix with homogeneously precipitated, nanoscale ordered γ′ precipitates similar to that found in traditional Ni-based superalloys with a significantly greater Ni content. Scanning electron microscopy, transmission electron microscopy, atom probe tomography, and CALPHAD-based thermodynamic modeling were employed to determine the phase stabilities and microstructural evolution in an age-hardenable 44.56Ni-26.6Fe-19.2Cr-1.0Co-3.4Al-4.4Ti-0.7Mo-0.14 C (at%) alloy. The primary heat treatment of solution annealing at 1121 °C for 4 h followed by age-hardening at 760 °C for 16 h resulted in a microstructure consisting of fine γ′ precipitates in an austenitic matrix along with grain boundary precipitates of carbides and other minor phases. Long-term aging at 900 °C for 250 h resulted in the coarsening of γ′ precipitates along with a change in the morphology from an initial spherical to a more cuboidal shape. In addition, the formation of plate-like η phase precipitates was observed, concomitant with the partial dissolution of the γ′ phase. The ability of computational thermodynamic models to predict microstructural characteristics is discussed.}, journal={Journal of Alloys and Compounds}, author={Gwalani, Bharat and Shukla, Shivakant and Leonard, Donovan and Poplawsky, Jonathan D. and Pierce, Dean T. and Kovarik, Libor and Muralidharan, Govindarajan and Devaraj, Arun}, year={2021}, month={Dec}, pages={161207} }
 @article{frank_nene_chen_gwalani_kautz_devaraj_an_mishra_2020, title={Correlating work hardening with co-activation of stacking fault strengthening and transformation in a high entropy alloy using in-situ neutron diffraction}, volume={10}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-020-79492-8}, DOI={10.1038/s41598-020-79492-8}, abstractNote={Abstract}, number={1}, journal={Scientific reports}, publisher={Springer Science and Business Media LLC}, author={Frank, Michael and Nene, Saurabh S. and Chen, Yan and Gwalani, Bharat and Kautz, Elizabeth J. and Devaraj, Arun and An, Ke and Mishra, Rajiv S.}, year={2020}, pages={22263} }
 @article{gwalani_dasari_soni_jagetia_agrawal_shukla_mishra_banerjee_2020, title={Deformation Twinning in a Metal-Intermetallic System: Novel Paradigm for Designing Alloys with Exceptional Strength-Ductility Combination}, volume={8}, url={https://doi.org/10.31224/osf.io/95tn4}, DOI={10.31224/osf.io/95tn4}, abstractNote={Engineering applications of high strength alloys are often restricted due to their poor tensile elongation or ductility. Alloys with high yield strength typically exhibit limited strain-hardenability (the difference between tensile and yield-strengths), leading to reduced tensile ductility. Deformation twinning, resulting in high strain hardenability, can lead to enhanced tensile elongation in single-phase solid solutions, including high entropy alloys (HEAs). However, alloy systems involving a solid solution matrix strengthened with an intermetallic phase do not exhibit deformation twinning, thus limiting their tensile ductility. We have successfully exploited deformation twinning in a novel HEA, strengthened using nano-lamellar ordered multi-component intermetallic precipitates, leading to an exceptionally high yield strength (~1630 MPa), good tensile ductility (~15%), and ultimate tensile strength (~1720 MPa), higher than any other reported fcc based alloy. Exploiting deformation twinning in a two-phase metal-intermetallic system, offers a new paradigm for addressing the strength-ductility trade-off plaguing alloy design.}, publisher={Open Engineering Inc}, author={Gwalani, Bharat and Dasari, Sriswaroop and Soni, Vishal and Jagetia, Abhinav and Agrawal, Priyanshi and shukla, Shivakant and Mishra, Rajiv S and Banerjee, Raj}, year={2020}, month={Aug} }
 @article{hasannaeimi_muskeri_gwalani_hofmann_mukherjee_2020, title={Deformation behavior of metallic glass composites and plasticity accommodation at microstructural length-scales}, volume={24}, DOI={10.1016/j.mtcomm.2020.101237}, abstractNote={Abstract Bulk metallic glass matrix composites represent a unique microstructural design strategy for overcoming the strength/ductility trade-off in structural alloys. Site-specific mechanical behavior of a Ti-based bulk metallic glass composite was evaluated at microstructural length-scale. The micro-pillars on the amorphous matrix showed an average yield point of 1.9 GPa followed by serrated plastic deformation characteristic of shear banding. In contrast, micro-pillars on the crystalline dendritic phase showed a much lower yield strength of 0.72 GPa on average for the four different crystallographic orientations chosen, smooth plastic flow with no recognizable load burst, and stable strain-hardening after yield point. A number of micro-pillars were made at the interface between the glassy matrix and the crystalline dendrite. The mixed micro-pillars showed homogeneous deformation and greater plasticity which was attributed to their smaller stored elastic energy. Shear bands initiated in the amorphous matrix were arrested by the crystalline dendrite, which accommodated plasticity through slip bands and dislocations pile-ups. The interface remained intact after plastic deformation, with no observable signs of devitrification in the amorphous phase.}, journal={Materials Today Communications}, author={Hasannaeimi, Vahid and Muskeri, Saideep and Gwalani, Bharat and Hofmann, Douglas C. and Mukherjee, Sundeep}, year={2020}, month={Sep}, pages={101237} }
 @article{gwalani_wang_jagetia_gangireddy_muskeri_mukherjee_lloyd_banerjee_mishra_2020, title={Dynamic Shear Deformation of a Precipitation Hardened Al<sub>0.7</sub>CoCrFeNi Eutectic High-Entropy Alloy Using Hat-Shaped Specimen Geometry}, volume={22}, url={https://www.mdpi.com/1099-4300/22/4/431}, DOI={10.3390/e22040431}, abstractNote={Lamellar eutectic structure in Al0.7CoCrFeNi high-entropy alloy (HEA) is emerging as a promising candidate for structural applications because of its high strength-ductility combination. The alloy consists of a fine-scale lamellar fcc + B2 microstructure with high flow stresses > 1300 MPa under quasi-static tensile deformation and >10% ductility. The response to shear loading was not investigated so far. This is the first report on the shear deformation of a eutectic structured HEA and effect of precipitation on shear deformation. A split-Hopkinson pressure bar (SHPB) was used to compress the hat-shaped specimens to study the local dynamic shear response of the alloy. The change in the width of shear bands with respect to precipitation and deformation rates was studied. The precipitation of L12 phase did not delay the formation of adiabatic shear bands (ASB) or affect the ASB width significantly, however, the deformed region around ASB, consisting of high density of twins in fcc phase, was reduced from 80 µm to 20 µm in the stronger precipitation strengthened condition. We observe dynamic recrystallization of grains within ASBs and local mechanical response of individual eutectic lamellae before and after shear deformation and within the shear bands was examined using nano-indentation.}, number={4}, journal={Entropy}, publisher={MDPI AG}, author={Gwalani, Bharat and Wang, Tianhao and Jagetia, Abhinav and Gangireddy, Sindhura and Muskeri, Saideep and Mukherjee, Sundeep and Lloyd, Jeffrey T. and Banerjee, Rajarshi and Mishra, Rajiv S.}, year={2020}, month={Apr}, pages={431} }
 @article{gwalani_wang_jagetia_gangireddy_muskeri_mukherjee_lloyd_banerjee_mishra_2020, title={Dynamic Shear Deformation of a Precipitation Hardened Al<sub>0.7</sub>CoCrFeNi Eutectic High-Entropy Alloy Using Hat-Shaped Specimen Geometry}, volume={3}, url={https://doi.org/10.20944/preprints202003.0154.v1}, DOI={10.20944/preprints202003.0154.v1}, abstractNote={Lamellar eutectic structure of Al0.7CoCrFeNi high-entropy alloy (HEA) is emerging as a promising candidate for structural applications because of its high strength-ductility combination. The alloy consists of a fine-scale lamellar fcc+B2 microstructure with high flow stresses >1500 MPa under quasi-static conditions. The response to shear loading was not investigated so far. This is the first report on the shear deformation of an eutectic structured HEA and effect of precipitation on shear deformation.  The dynamic shear response (DSR) of the eutectic HEA was examined in two microstructural conditions, with and without the presence of L12 precipitates. A split-Hopkinson pressure bar (SHPB) was used to compress the hat-shaped specimens to study the local DSR of the alloy. The adiabatic shear bands (ASBs) in two different microstructural conditions were characterized after deformation at dynamic strain rates. The adiabatic shear localization occurs at low strains for the high strength material, and the eutectic microstructure does not delay cracking. The width of ASBs and the extent of plastic deformation around them has been correlated with the rate of straining. Dynamic recrystallization within ASBs and profuse twinning around it was observed. Local mechanical response of individual lamellae before and after shear deformation was examined using nano-indentation.}, publisher={MDPI AG}, author={Gwalani, Bharat and Wang, Tianhao and Jagetia, Abhinav and Gangireddy, Sindhura and Muskeri, Saideep and Mukherjee, Sundeep and Lloyd, Jeffrey T. and Banerjee, Rajarshi and Mishra, Rajiv S.}, year={2020}, month={Mar} }
 @article{dasari_jagetia_chang_soni_gwalani_gorsse_yeh_banerjee_2020, title={Engineering multi-scale B2 precipitation in a heterogeneous FCC based microstructure to enhance the mechanical properties of a Al0. 5Co1. 5CrFeNi1. 5 high entropy alloy}, volume={830}, DOI={10.1016/j.jallcom.2020.154707}, abstractNote={While ordered L12 or gamma prime precipitates in face centered cubic (FCC) based microstructures have been extensively used for strengthening nickel or cobalt base superalloys, and more recently in high entropy alloys (HEAs) or complex concentrated alloys (CCAs), the possibility of exploiting ordered B2 precipitates in FCC-based systems has been relatively less investigated. The present study shows the propensity of developing a heterogeneous microstructure, consisting of two different distributions of FCC grain sizes, and two different size scales of B2 precipitates, within an FCC-based Al0.5Co1.5CrFeNi1.5 HEA/CCA. This alloy composition has been designed using solution thermodynamics-based modeling such that it has a high phase fraction and solvus temperature of the B2 phase. The resulting heterogenous microstructure exhibited an approximately 400% increase in yield strength with respect to the single-phase FCC solid solution condition of the same alloy while maintaining very good tensile ductility ∼20%.}, journal={Journal of Alloys and Compounds}, author={Dasari, Sriswaroop and Jagetia, Abhinav and Chang, Y.-J. and Soni, Vishal and Gwalani, Bharat and Gorsse, Stéphane and Yeh, A.-C. and Banerjee, Rajarshi}, year={2020}, month={Jul}, pages={154707} }
 @article{dasari_jagetia_soni_gwalani_gorsse_banerjee_2020, title={Engineering transformation pathways in an Al0. 3CoFeNi complex concentrated alloy leads to excellent strength–ductility combination}, volume={8}, DOI={10.1080/21663831.2020.1777215}, abstractNote={Guided by thermodynamic modeling, engineering phase transformation pathways via thermo-mechanical processing, in a complex concentrated alloy/high entropy alloy (HEA) of composition Al0.3CoFeNi, lead to a novel multi-scale microstructure consisting of fine-scale FCC + L12 grains mixed with B2 + BCC grains. The two-step pathway comprises initial decomposition of the parent single-phase FCC to form a fine-grained FCC + B2 microstructure, which further decomposes in the second step into the complex four-phase mixture, exhibiting an excellent combination of tensile yield stress of ∼1490 MPa, ultimate tensile strength of ∼1663 MPa, with a good ductility of ∼12% at room temperature. Impact statement This paper reports a novel multi-phase microstructure in a HEA/CCA similar to the microstructure observed in dual-phase stainless steel. This report exemplifies the novelty of HEA/CCA compositional space. GRAPHICAL ABSTRACT}, number={11}, journal={Materials Research Letters}, author={Dasari, Sriswaroop and Jagetia, Abhinav and Soni, Vishal and Gwalani, Bharat and Gorsse, Stéphane and Banerjee, Rajarshi}, year={2020}, pages={399–407} }
 @article{gwalani_olszta_varma_li_soulami_kautz_pathak_rohatgi_sushko_mathaudhu_et al._2020, title={Extreme shear-deformation-induced modification of defect structures and hierarchical microstructure in an Al–Si alloy}, volume={1}, url={http://dx.doi.org/10.1038/s43246-020-00087-x}, DOI={10.1038/s43246-020-00087-x}, abstractNote={Abstract}, number={1}, journal={Communications Materials}, publisher={Springer Science and Business Media LLC}, author={Gwalani, Bharat and Olszta, Matthew and Varma, Soumya and Li, Lei and Soulami, Ayoub and Kautz, Elizabeth and Pathak, Siddhartha and Rohatgi, Aashish and Sushko, Peter V. and Mathaudhu, Suveen and et al.}, year={2020}, month={Dec} }
 @article{dasari_gwalani_jagetia_soni_gorsse_banerjee_2020, title={Hierarchical Eutectoid Nano-lamellar Decomposition in an Al 0.3 CoFeNi Complex Concentrated Alloy}, volume={10}, DOI={10.1038/s41598-020-61538-6}, abstractNote={Abstract}, journal={Scientific reports}, author={Dasari, Sriswaroop and Gwalani, Bharat and Jagetia, Abhinav and Soni, Vishal and Gorsse, Stéphane and Banerjee, Rajarshi}, year={2020}, pages={4836} }
 @article{dasari_chaudhary_gwalani_jagetia_soni_gorsse_ramanujan_banerjee_2020, title={Highly tunable magnetic and mechanical properties in an Al0.3CoFeNi complex concentrated alloy}, volume={12}, url={https://doi.org/10.1016/j.mtla.2020.100755}, DOI={10.1016/j.mtla.2020.100755}, abstractNote={Electrical rotating machines, including motors, account for a significant portion of total energy consumption in the world. Improving the magnetic materials used in motors is a key challenge to increase their performance. Specifically, higher rotation frequency requires appropriate site specific magnetic properties as well as good mechanical properties. Hence, we studied both the magnetic and mechanical properties of an Al0.3CoFeNi complex concentrated alloy (CCA). Heat treatment, guided by phase diagram modeling, was employed to develop a novel eutectoid-like nano-lamellar (FCC+L12) / (BCC+B2) microstructure as well as a coarser FCC+B2 microstructure. The coarser microstructure exhibits soft magnetic properties with saturation magnetization (Ms) of ~127 emu/g, coercivity (Hc) of ~151 A/m and microhardness of ~ 195 VHN. On the other hand, the semi-hard nano-lamellar microstructure exhibits Ms ~138 emu/g, a high Hc ~12,732 A/m and a very high microhardness ~ 513 VHN. This corresponds to more than eighty times increase in Hc and double the hardness in the same alloy. These results demonstrate the feasibility of producing a range of mechanical and magnetic properties by thermo-mechanical treatment of a single CCA composition, making them potential candidates for metamorphic manufacturing.}, journal={Materialia}, publisher={Elsevier BV}, author={Dasari, Sriswaroop and Chaudhary, Varun and Gwalani, Bharat and Jagetia, Abhinav and Soni, Vishal and Gorsse, Stephane and Ramanujan, Raju V. and Banerjee, Rajarshi}, year={2020}, month={Aug}, pages={100755} }
 @article{chaudhary_soni_gwalani_ramanujan_banerjee_2020, title={Influence of non-magnetic Cu on enhancing the low temperature magnetic properties and Curie temperature of FeCoNiCrCu (x) high entropy alloys}, volume={182}, DOI={10.1016/j.scriptamat.2020.02.037}, abstractNote={The microstructure and magnetic properties of three face-centered cubic (FCC) FeCoNiCrCu(x) high entropy alloys (HEAs) (x = 0, 0.5, 1) are investigated. Interestingly, addition of the nonmagnetic element Cu to FeCoNiCr HEA is found to enhance exchange interactions and low temperature saturation magnetization. The paramagnetic to ferromagnetic Curie transition temperature increases from 85 K for FeCoNiCr to 118 K for FeCoNiCrCu. This is counterintuitive since Cu is nonmagnetic; however, atom probe tomography revealed Cu rich clusters containing 5 at% Ni and 1 at% each of Fe, Co, Cr, within FCC matrix, these clusters altered the matrix composition and consequently its magnetic properties.}, journal={Scripta Materialia}, author={Chaudhary, Varun and Soni, Vishal and Gwalani, Bharat and Ramanujan, Raju V. and Banerjee, Rajarshi}, year={2020}, month={Jun}, pages={99–103} }
 @article{gwalani_choudhuri_liu_lloyd_mishra_banerjee_2020, title={Interplay between single phase solid solution strengthening and multi-phase strengthening in the same high entropy alloy}, volume={771}, DOI={10.1016/j.msea.2019.138620}, abstractNote={High entropy alloys (HEAs) offer the opportunity to achieve an unprecedented balance of properties by accessing novel multi-scale microstructural combinations. Despite the large range of combinations of strength and ductility reported in HEAs, the complex interplay between multiple strengthening mechanisms has not been addressed. The single-phase fcc solid solution state of the Al0.3CoCrFeNi alloy exhibits a strong Hall-Petch hardening effect with reducing grain size. While the same alloy can be strengthened by a composite-reinforcement effect of hard intermetallic B2 and sigma precipitates, within a fine-grained fcc matrix. Such precipitation leads to solute depletion within the parent fcc matrix, resulting in a substantially reduced Hall-Petch hardening effect. Additional formation of nano-clusters within the fcc matrix can strengthen the same alloy to 1.85 GPa at room temperature, via an Orowan strengthening mechanism. This paper presents the complex interplay between strengthening mechanisms operative at different length scales.}, journal={Materials Science and Engineering: A}, author={Gwalani, Bharat and Choudhuri, Deep and Liu, Kaimiao and Lloyd, J.T. and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2020}, month={Jan}, pages={138620} }
 @article{wang_gwalani_silverstein_darsell_jana_roosendaal_ortiz_daye_pelletiers_whalen_2020, title={Microstructural Assessment of a Multiple-Intermetallic-Strengthened Aluminum Alloy Produced from Gas-Atomized Powder by Hot Extrusion and Friction Extrusion}, volume={13}, url={https://doi.org/10.3390/ma13235333}, DOI={10.3390/ma13235333}, abstractNote={An aluminum (Al) matrix with various transition metal (TM) additions is an effective alloying approach for developing high-specific-strength materials for use at elevated temperatures. Conventional fabrication processes such as casting or fusion-related methods are not capable of producing Al–TM alloys in bulk form. Solid phase processing techniques, such as extrusion, have been shown to maintain the microstructure of Al–TM alloys. In this study, extrusions are fabricated from gas-atomized aluminum powders (≈100–400 µm) that contain 12.4 wt % TM additives and an Al-based matrix reinforced by various Al–Fe–Cr–Ti intermetallic compounds (IMCs). Two different extrusion techniques, conventional hot extrusion and friction extrusion, are compared using fabricating rods. During extrusion, the strengthening IMC phases were extensively refined as a result of severe plastic deformation. Furthermore, the quasicrystal approximant IMC phase (70.4 wt % Al, 20.4 wt % Fe, 8.7 wt % Cr, 0.6 wt % Ti) observed in the powder precursor is replaced by new IMC phases such as Al3.2Fe and Al45Cr7-type IMCs. The Al3Ti-type IMC phase is partially dissolved into the Al matrix during extrusion. The combination of linear and rotational shear in the friction extrusion process caused severe deformation in the powders, which allowed for a higher extrusion ratio, eliminated linear voids, and resulted in higher ductility while maintaining strength comparable to that resulting from hot extrusion. Results from equilibrium thermodynamic calculations show that the strengthening IMC phases are stable at elevated temperatures (up to ≈ 600 °C), thus enhancing the high-temperature strength of the extrudates.}, number={23}, journal={Materials}, publisher={MDPI AG}, author={Wang, Tianhao and Gwalani, Bharat and Silverstein, Joshua and Darsell, Jens and Jana, Saumyadeep and Roosendaal, Timothy and Ortiz, Angel and Daye, Wayne and Pelletiers, Tom and Whalen, Scott}, year={2020}, month={Nov}, pages={5333} }
 @article{soni_gwalani_alam_dasari_zheng_senkov_miracle_banerjee_2020, title={Phase inversion in a two-phase, BCC+ B2, refractory high entropy alloy}, volume={185}, DOI={10.1016/j.actamat.2019.12.004}, abstractNote={A phenomenon of “phase inversion”, presumably the first ever experimental evidence in metallic alloys, is shown in a refractory high entropy alloy (RHEA), Al0.5NbTa0.8Ti1.5V0.2Zr. Phase inversion in crystalline solid systems is driven by the differences in elastic modulus of the two phases. Quenching from a high temperature single phase field, the RHEA exhibits a co-continuous mixture of a disordered BCC and an ordered B2 phase, that upon isothermal annealing at 600 °C develops via spinodal decomposition into a continuous B2 matrix with discrete cuboidal BCC precipitates aligned along the 〈001〉 directions. Longer term annealing at 600 °C results in the development of necking constrictions along the B2 channels, eventually pinching-off these channels and making the BCC phase continuous with discrete B2 precipitates. This inversion process can be related to the simultaneous operation of two processes: (i) spheroidization of the initially discrete cuboidal BCC precipitates driven by a reduction in the total interface energy and (ii) an increase in the stiffness of the B2 phase, relative to the BCC phase, due to chemical composition changes during annealing, forcing the B2 regions to become discrete driven by the reduction in the total elastic strain energy.}, journal={Acta Materialia}, author={Soni, Vishal and Gwalani, Bharat and Alam, Talukder and Dasari, Sriswaroop and Zheng, Yufeng and Senkov, Oleg N. and Miracle, Daniel and Banerjee, Rajarshi}, year={2020}, month={Feb}, pages={89–97} }
 @article{soni_senkov_couzinie_zheng_gwalani_banerjee_2020, title={Phase stability and microstructure evolution in a ductile refractory high entropy alloy Al10Nb15Ta5Ti30Zr40}, volume={9}, DOI={10.1016/j.mtla.2019.100569}, abstractNote={This paper reports the microstructural evolution and phase stability in a newly developed low-density Al10Nb15Ta5Ti30Zr40 refractory high entropy alloy (RHEA) at different temperatures. This alloy composition was adapted from the composition of the B2 phase in a two-phase B2+BCC mixture at 1000°C in the refractory high entropy superalloy Al0.25NbTaTiZr. After homogenizing at a high-temperature, followed by fast or slow cooling to room temperature, this alloy exhibited a nano-scale mixture of co-continuous BCC and B2 phases, resembling a spinodally decomposed microstructure with concurrent ordering. Interestingly, this novel nano-scale BCC+B2 microstructure exhibits excellent room temperature compressive yield strength (~1075MPa) and ductility (true strain at failure ~0.55). Annealing at 600°C and 750°C resulted in the formation of additional ordered omega type AlZr2 phase in this alloy. The experimentally observed phase evolution is in fair agreement with CALPHAD predictions.}, journal={Materialia}, author={Soni, V. and Senkov, O.N. and Couzinie, J.-P. and Zheng, Y. and Gwalani, B. and Banerjee, R.}, year={2020}, month={Mar}, pages={100569} }
 @article{kautz_gwalani_lambeets_kovarik_schreiber_perea_senor_liu_battu_tseng_et al._2020, title={Rapid assessment of structural and compositional changes during early stages of zirconium alloy oxidation}, url={https://doi.org/10.1038/s41529-020-00133-6}, DOI={10.1038/s41529-020-00133-6}, abstractNote={Abstract}, journal={npj Materials Degradation}, author={Kautz, Elizabeth J. and Gwalani, Bharat and Lambeets, Sten V. M. and Kovarik, Libor and Schreiber, Daniel K. and Perea, Daniel E. and Senor, David and Liu, Yi-Sheng and Battu, Anil K. and Tseng, Kuo-Pin and et al.}, year={2020}, month={Sep} }
 @article{dutt_gwalani_tungala_carl_mishra_tamirisakandala_young_cho_brennan_2019, title={A novel nano-particle strengthened titanium alloy with exceptional specific strength}, volume={9}, DOI={10.1038/s41598-019-48139-8}, abstractNote={Abstract}, journal={Scientific reports}, author={Dutt, Aniket K. and Gwalani, Bharat and Tungala, Vedavyas and Carl, Matthew and Mishra, Rajiv S. and Tamirisakandala, Sesh A. and Young, Marcus L. and Cho, Kyu C. and Brennan, Raymond E.}, year={2019}, pages={11726} }
 @article{gwalani_salloom_alam_valentin_zhou_thompson_srinivasan_banerjee_2019, title={Composition-dependent apparent activation-energy and sluggish grain-growth in high entropy alloys}, volume={7}, DOI={10.1080/21663831.2019.1601644}, abstractNote={ABSTRACT Experimental results reveal that the apparent activation-energy for grain-growth in an fcc-based AlxCoCrFeNi high entropy alloy (HEA) system increases from 179 to 486 kJ/mol when the Al content increases from x = 0.1 to 0.3. These unexpectedly high apparent activation-energy values can be potentially attributed to solute clustering within the fcc solid-solution phase that develops with increasing Al content in this HEA. Detailed microstructural analysis using atom-probe tomography and density functional theory (DFT) calculations strongly indicate the presence of such nanoscale clusters. This phenomenon can change grain-growth from a classical solute-drag regime to a much more sluggish cluster-drag based mechanism in these HEAs. GRAPHICAL ABSTRACT IMPACT STATEMENT First report on a composition dependent change in apparent activation-energy for grain-growth in high entropy alloys. A novel cluster drag effect inhibiting grain-growth kinetics is suggested.}, number={7}, journal={Materials Research Letters}, author={Gwalani, Bharat and Salloom, Riyadh and Alam, Talukder and Valentin, Sheena G. and Zhou, Xuyang and Thompson, G. and Srinivasan, S.G. and Banerjee, Rajarshi}, year={2019}, pages={267–274} }
 @article{gwalani_gangireddy_shukla_yannetta_valentin_mishra_banerjee_2019, title={Compositionally graded high entropy alloy with a strong front and ductile back}, volume={20}, DOI={10.1016/j.mtcomm.2019.100602}, abstractNote={Abstract Material components with graded properties can be ideal for many advanced applications due to their seamless nature of microstructural transition, cost reduction and high resistance of failure. A compositionally graded AlXCoCrFeNi (x = 0.3–0.7) high entropy alloy composite build was additively manufactured using laser engineered net shaping (LENS™). In this high throughput production process, the elemental composition of Al-Co-Cr-Fe-Ni powders in the hoppers were varied and the feed rates were tuned to create a laminate of Al0.3CoCrFeNi and Al0.7CoCrFeNi layers, with a 500 μm wide transition zone of intermediary composition. The energy dispersive X-ray spectroscopy along the build direction verified the elemental composition matching closely with the targeted compositions. X-ray diffraction revealed the Al0.3CoCrFeNi to be a single-phase face centered cubic (fcc) structure whereas Al0.7CoCrFeNi had dual phase fcc + B2. Scanning electron microscopy was used to capture the microstructural features in the two layers as well as the transition zone. The massive shift in mechanical properties of hardness, dynamic strength and work hardening rates in this graded composite have been discussed. With this endeavor, microstructural complexity of HEAs has been combined with unique advantage of LENS™ to achieve ingenious path to fabricate materials suited applications demanding variable strength and ductility/toughness.}, journal={Materials Today Communications}, author={Gwalani, Bharat and Gangireddy, Sindhura and Shukla, Shivakant and Yannetta, Christopher J. and Valentin, Sheena Grace and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2019}, month={Sep}, pages={100602} }
 @article{gangireddy_gwalani_soni_banerjee_mishra_2019, title={Contrasting mechanical behavior in precipitation hardenable AlXCoCrFeNi high entropy alloy microstructures: Single phase FCC vs. dual phase FCC-BCC}, volume={739}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/j.msea.2018.10.021}, DOI={10.1016/j.msea.2018.10.021}, abstractNote={AlxCoCrFeNi is a prominent high entropy alloy system with varying crystal structure from FCC to BCC depending on aluminum content. The mechanical behavior of Al0.7CoCrFeNi with dual phase FCC+BCC microstructure has been compared with that of single phase FCC Al0.3CoCrFeNi. Both quasi-static and dynamic strain rate regimes were investigated. Hypo-eutectic Al0.7CoCrFeNi showed much higher strength due to fine lamellar microstructure with a large number of FCC-BCC interphase boundaries. But this also leads to lower strain rate sensitivity due to the long-range nature of these interfaces, overcoming them is indifferent with temperature elevation to assist slip, thus making them athermal barriers. Both these precipitation hardenable alloys were aged to induce precipitation of ordered L12 in the FCC phase. This coherent nano-scale L12 precipitate caused a significant increase in the yield strength of both single-phase and dual phase structures while reducing the strain rate sensitivity (SRS) only slightly. L12 precipitation in FCC matrix greatly enhanced twinning during dynamic deformation. Large-scale deformation twins were observed in coarse Al0.3CoCrFeNi FCC and FCC + L12 microstructures. The scale of deformation twins was much smaller in the dual phase Al0.7CoCrFeNi whose refined lamellae width retarded twinning. The lamellar structures, nevertheless, had higher work hardening due to their higher dislocation density storage capability.}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Gangireddy, Sindhura and Gwalani, Bharat and Soni, Vishal and Banerjee, Rajarshi and Mishra, Rajiv S.}, year={2019}, month={Nov}, pages={158–166} }
 @article{mantri_sun_choudhuri_alam_gwalani_prima_banerjee_2019, title={Deformation Induced Hierarchical Twinning Coupled with Omega Transformation in a Metastable β-Ti Alloy}, volume={9}, ISSN={2045-2322}, DOI={10.1038/s41598-018-37865-0}, abstractNote={Abstract}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Mantri, S. A. and Sun, F. and Choudhuri, D. and Alam, T. and Gwalani, B. and Prima, F. and Banerjee, R.}, year={2019}, month={Feb}, pages={1334} }
 @article{choudhuri_shukla_gwalani_banerjee_mishra_2019, title={Deformation induced intermediate metastable lattice structures facilitate ordered B2 nucleation in a fcc-based high entropy alloy}, volume={7}, ISSN={2166-3831}, url={http://dx.doi.org/10.1080/21663831.2018.1553212}, DOI={10.1080/21663831.2018.1553212}, abstractNote={ABSTRACT Ordered B2 precipitates typically nucleate at the grains-boundaries of fcc-based high entropy alloys. Here, we report a novel mixed-mode coupled displacive-diffusional transformation resulting in homogeneously distributed intra-granular B2 precipitates within the fcc matrix. Severe plastic deformation forms compositionally invariant, metastable distorted fcc structures, resembling hexagon-like templates, at the deformation twin-boundaries. These shear-induced hexagon-like templates correspond to the symmetry of the {111}bcc planes, and act as sites for B2 nucleation, establishing the fcc-bcc Kurdjumov–Sachs (KS) orientation relationship. However, the composition of these B2 precipitates is far-from-equilibrium. Subsequent isothermal annealing causes solute partitioning driving the composition of the B2 precipitates towards equilibrium. GRAPHICAL ABSTRACT IMPACT STATEMENT For the first time, a mixed mode displacive-diffusional fcc-to-bcc-ordered B2 transformation mechanism was revealed in a deformed fcc-based Al0.3CoCrFeNi complex concentrated or high entropy alloy.}, number={1}, journal={Materials Research Letters}, publisher={Informa UK Limited}, author={Choudhuri, Deep and Shukla, Shivakant and Gwalani, Bharat and Banerjee, Rajarshi and Mishra, Rajiv S.}, year={2019}, month={Dec}, pages={40–46} }
 @article{wang_gwalani_shukla_frank_mishra_2019, title={Development of in situ composites via reactive friction stir processing of Ti–B4C system}, volume={172}, DOI={10.1016/j.compositesb.2019.05.067}, abstractNote={In situ titanium matrix composites were fabricated by introducing an exothermic reaction between Ti and B4C during friction stir processing (FSP). Formation of TiB, TiB2, and TiC was confirmed by X-ray diffraction and transmission electron microscopy along with energy dispersive X-ray spectroscopy and diffraction pattern. TiB and TiB2 whiskers and TiC particles influenced the dynamic recrystallization process, which facilitated an equiaxed grained structure rather than the Widmanstätten microstructure. Mechanical properties of as-received Ti–6Al–4V including hardness, elastic modulus, compressive yield strength and work-hardening rate (stage B) were improved by ∼ 57%, 17%, 47% and 100%, respectively, after FSP with B4C.}, journal={Composites Part B: Engineering}, author={Wang, Tianhao and Gwalani, Bharat and Shukla, Shivakant and Frank, Michael and Mishra, Rajiv S.}, year={2019}, month={Sep}, pages={54–60} }
 @article{liu_gwalani_komarasamy_shukla_wang_mishra_2019, title={Effect of nano-sized precipitates on the fatigue property of a lamellar structured high entropy alloy}, volume={760}, DOI={10.1016/j.msea.2019.06.012}, abstractNote={Fatigue damage is inevitable and destructive for in-service structural materials and hence warrants a detailed examination of the fatigue behavior of potential structural materials such as high entropy alloys (HEAs). This study focused on investigation of the mechanical properties of Al0.7CoCrFeNi HEA with two microstructural conditions; i.e., a lamellar structure consisting of FCC + B2 phases (a) without precipitates and (b) with nano-sized L12 precipitates in the FCC phase. Nano-sized L12 precipitates were introduced in FCC through low-temperature annealing. Although the nano-sized L12 precipitates enhanced tensile strength, no improvement in fatigue properties was noted. For both conditions, crack initiation and propagation were observed along persistent slip bands and FCC/B2 phase boundaries.}, journal={Materials Science and Engineering: A}, author={Liu, Kaimiao and Gwalani, Bharat and Komarasamy, Mageshwari and Shukla, Shivakant and Wang, Tianhao and Mishra, Rajiv S.}, year={2019}, month={Jul}, pages={225–230} }
 @article{wang_shukla_gwalani_komarasamy_reza-nieto_mishra_2019, title={Effect of reactive alloy elements on friction stir welded butt joints of metallurgically immiscible magnesium alloys and steel}, volume={39}, DOI={10.1016/j.jmapro.2019.02.009}, abstractNote={Magnesium alloys (AZ31 and WE43) and steel (316 stainless steel, SS316) were butt welded through friction stir welding. Even though Mg and Fe are metallurgically immiscible, intermetallic compounds (IMCs) formed at the welded interface due to the existence of alloying elements in both magnesium alloys and steel. The formation of IMCs among alloying elements and the matrix were verified by thermodynamic and kinetic calculations and microstructural characterization. The elastic modulus mismatch and resultant stress concentration during tensile testing lead to interfacial fracture and the very existence of IMCs impaired dissimilar joint strength due to the brittleness of the IMCs.}, journal={Journal of Manufacturing Processes}, author={Wang, Tianhao and Shukla, Shivakant and Gwalani, Bharat and Komarasamy, Mageshwari and Reza-Nieto, Luis and Mishra, Rajiv S.}, year={2019}, month={Mar}, pages={138–145} }
 @article{bantounas_gwalani_alam_banerjee_dye_2019, title={Elemental partitioning, mechanical and oxidation behaviour of two high-γ′ W-free γ/γ′ polycrystalline Co/Ni superalloys}, volume={163}, DOI={10.1016/j.scriptamat.2018.12.025}, abstractNote={Cr-containing W-free Co alloys that form L12γ′ strengthening precipitates in an fcc γ matrix are presented to examine the effect of Ta and Nb additions to increase the strength, solvus temperature and gamma prime fraction. The alloys are found to have relatively low density, good oxidation resistance (<0.5 μm scale at 800 °C for 100 h) with coherent Al2O3 and Cr2O3 scales, and reasonable yield strengths, ∼800 MPa. The phase partitioning, measured by atom probe tomography, was found to be similar to W-containing Co/Ni superalloys, with Mo partitioning to the matrix providing solid solution strengthening.}, journal={Scripta Materialia}, author={Bantounas, Ioannis and Gwalani, Bharat and Alam, Talukder and Banerjee, Rajarshi and Dye, David}, year={2019}, month={Apr}, pages={44–50} }
 @article{choudhuri_gwalani_gorsse_komarasamy_mantri_srinivasan_mishra_banerjee_2019, title={Enhancing strength and strain hardenability via deformation twinning in fcc-based high entropy alloys reinforced with intermetallic compounds}, volume={165}, DOI={10.1016/j.actamat.2018.12.010}, abstractNote={Twinning is a key deformation mechanism in face-centered-cubic (fcc)-based and some body-centered-cubic (bcc)-based alloys, which imparts excellent strength-ductility combination by increasing strain-hardenability. Typically, twinning in fcc-based alloys increases when the stacking fault energy is lowered via changes in composition. The present study clearly demonstrates that deformation twinning can be enhanced when hard-intermetallic compounds like ordered B2 and sigma phases form in the fcc matrix of a high entropy alloy (HEA), leading to an excellent combination of strength, ductility, and strain-hardenability. Such a combination of properties was achieved by exploiting the novel and often unusual phase stability regimes that can be accessed in these complex concentrated HEAs. The present study exploits a unique three-phase mixture of recrystallized fine-grained fcc + B2 + sigma in a prototypical Al0.3CoCrFeNi HEA to demonstrate this effect. Coupling transmission electron microscopy and molecular dynamics simulations revealed that B2 grains enhance deformation twinning by raising the local stress levels, consequently forming substantially thicker twins as compared to the single fcc-phase condition of Al0.3CoCrFeNi. The local stresses were further accommodated via nano-twinning, limited B2 plasticity, and highly restricted micro-cracks in and around the sigma grains.}, journal={Acta Materialia}, author={Choudhuri, Deep and Gwalani, Bharat and Gorsse, Stephane and Komarasamy, Mageshwari and Mantri, Srinivas A. and Srinivasan, Srivilliputhur G. and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2019}, month={Feb}, pages={420–430} }
 @article{korir_gwalani_joseph_kamras_arvapally_omary_marpu_2019, title={Facile photochemical syntheses of conjoined nanotwin gold-silver particles within a biologically-benign chitosan polymer}, volume={9}, DOI={10.3390/nano9040596}, abstractNote={A simple photochemical method for making conjoined bi-metallic gold-silver (Au/Ag) nanotwins, a new breed of nanoparticles (NPs), is developed. To the best of our knowledge, the photochemical method resulted in distinct, conjoined, bimetallic nanotwins that are different from any well-established alloyed or core-shell nanostructures in the literature. The conjoined Au-Ag NPs possessed surface plasmon resonance (SPR) properties of both metals. The bimetallic nanostructures possessing distinctive optical properties of both metals were obtained using Au NPs as seeds in the first step, followed by the addition of a silver precursor as feed in the second step during a photochemical irradiation process. In the first step, small, isotropic or large, anisotropic Au NPs are generated by photoinduced reduction within a biocompatible chitosan (CS) polymer. In the second step, a silver precursor (AgNO3) is added as the feed to the AuNPs seed, followed by irradiation of the solution in the ice-bath. The entire photochemical irradiation process resulting in the formation of bimetallic Au-AgNPs did not involve any other reducing agents or stabilizing agents other than the CS polymer stabilizer. The small, conjoined Au-Ag bi-metallic NPs exhibited SPR with peak maxima centering at ~400 nm and ~550 nm, whereas the large conjoined nanoparticles exhibited SPR with peak maxima centering at ~400 nm, 550 nm, and 680 nm, characteristic of both gold and silver surface plasmons in solution. The tunability in the SPR and size of the bimetallic NPs were obtained by varying the reaction time and other reaction parameters, resulting in average sizes between 30 and 100 nm. The SPR, size, distribution, and elemental composition of the bi-metallic NPs were characterized using UV-Vis absorption, electron microscopy, and energy dispersive X-ray spectroscopy (EDS) studies.}, number={4}, journal={Nanomaterials}, author={Korir, Daniel K. and Gwalani, Bharat and Joseph, Abel and Kamras, Brian and Arvapally, Ravi K. and Omary, Mohammad A. and Marpu, Sreekar B.}, year={2019}, pages={596} }
 @article{liu_komarasamy_gwalani_shukla_mishra_2019, title={Fatigue behavior of ultrafine grained triplex Al0.3CoCrFeNi high entropy alloy}, volume={158}, ISSN={1359-6462}, url={http://dx.doi.org/10.1016/j.scriptamat.2018.08.048}, DOI={10.1016/j.scriptamat.2018.08.048}, abstractNote={Ultrafine grained (UFG) alloys suffer from limited strain hardening hence reduced ductility. Incorporation of deformation twinning can overcome this limitation. An Al0.3CoCrFeNi high-entropy alloy was thermo-mechanically processed to yield a UFG triplex microstructure (davg: 0.71 ± 0.35 μm) with FCC, and hard B2 and sigma phases. The annealed material exhibited an exceptional strength-ductility combination with ultimate tensile strength (UTS) of ~1.1 GPa and elongation of ~25%. Furthermore, the alloy showed excellent fatigue resistance with an endurance limit of ~0.43 UTS. Remarkable mechanical properties are attributed to the formation of extensive deformation nanotwins and increased dislocation accumulation capability.}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Liu, Kaimiao and Komarasamy, Mageshwari and Gwalani, Bharat and Shukla, Shivakant and Mishra, Rajiv S.}, year={2019}, month={Nov}, pages={116–120} }
 @article{gangireddy_gwalani_banerjee_mishra_2019, title={High Strain Rate Response of Al0.7CoCrFeNi High Entropy Alloy: Dynamic Strength Over 2 GPa from Thermomechanical Processing and Hierarchical Microstructure}, volume={5}, url={https://doi.org/10.1007/s40870-018-00178-4}, DOI={10.1007/s40870-018-00178-4}, number={1}, journal={Journal of Dynamic Behavior of Materials}, publisher={Springer Science and Business Media LLC}, author={Gangireddy, S. and Gwalani, B. and Banerjee, R. and Mishra, R. S.}, year={2019}, month={Mar}, pages={1–7} }
 @article{sinha_komarasamy_thapliyal_gwalani_shukla_darling_mishra_2019, title={Immiscible nanostructured copper-aluminum-niobium alloy with excellent precipitation strengthening upon friction stir processing and aging}, volume={164}, DOI={10.1016/j.scriptamat.2019.01.038}, abstractNote={A ternary immiscible nanostructured Cu-Al-Nb alloy was fabricated by friction stir processing of mechanically compacted pellets. Subsequently, aging was carried out at 563 K for various times. The material exhibited hardness of ~4.3 ± 0.1 GPa in the peak-aged condition (aging for 6 h), which is remarkable among Cu-based ternary immiscible alloys. The excellent strength of the material is attributed to Hall-Petch strengthening due to the extremely refined nanocrystalline structure, coupled with precipitation strengthening due to a uniform distribution of nano-scale Al- and Nb-rich precipitates or clusters, as confirmed by X-ray diffraction and microstructural characterization.}, journal={Scripta Materialia}, author={Sinha, Subhasis and Komarasamy, Mageshwari and Thapliyal, Saket and Gwalani, Bharat and Shukla, Shivakant and Darling, Kristopher A. and Mishra, Rajiv S.}, year={2019}, month={Apr}, pages={42–47} }
 @article{gwalani_gangireddy_zheng_soni_mishra_banerjee_2019, title={Influence of ordered L1 2 precipitation on strain-rate dependent mechanical behavior in a eutectic high entropy alloy}, volume={9}, DOI={10.1038/s41598-019-42870-y}, abstractNote={Abstract}, journal={Scientific reports}, author={Gwalani, Bharat and Gangireddy, Sindhura and Zheng, Yufeng and Soni, Vishal and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2019}, pages={6371} }
 @article{gwalani_soni_waseem_mantri_banerjee_2019, title={Laser additive manufacturing of compositionally graded AlCrFeMoVx (x= 0 to 1) high-entropy alloy system}, volume={113}, DOI={10.1016/j.optlastec.2019.01.009}, abstractNote={The current study discusses a novel combinatorial high-throughput approach for assessing the composition-microstructure-hardness relationship, using laser deposited compositionally graded AlCrFeMoVx (0 < x < 1) high entropy alloy (HEA) as a candidate system. The composition gradient was achieved from AlCrFeMo (with 0.3 at. % V) to AlCrFeMoV (with 18.5 at. % V) over a length of ∼20 mm, deposited using the laser engineered net shaping process from a blend of elemental powders. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy were used to characterize the alloys. A single solid solution (SS) body-centered cubic (bcc) structure is observed throughout the compositional range. The high solubility of V in this novel alloy system offers a broad range of solid solution strengthening of a compositionally complex but structurally simple bcc matrix. The hardness of the alloy increases from 485 Hv to 581 Hv on increasing V from 0.3 to 18.5 at. %. The solid solution hardening model for dilute solutions underestimates the strengthening of the alloy. The current study presents a novel and efficient method for microstructural screening of the bulk alloys for optimization of the microstructure and properties.}, journal={Optics & Laser Technology}, author={Gwalani, Bharat and Soni, Vishal and Waseem, Owais Ahmed and Mantri, Srinivas Aditya and Banerjee, Rajarshi}, year={2019}, month={May}, pages={330–337} }
 @article{gangireddy_gwalani_liu_faierson_mishra_2019, title={Microstructure and mechanical behavior of an additive manufactured (AM) WE43-Mg alloy}, volume={26}, DOI={10.1016/j.addma.2018.12.015}, abstractNote={Magnesium alloys are highly attractive in aerospace and auto industries due to their high strength-to-weight ratio. Additive manufacturing of Mg alloys can further save cost from materials and machining time. This paper investigates the microstructure and dynamic mechanical behavior of WE-43 Mg alloy built through the powder bed fusion process. Samples from four different combinations of processing parameters were built. These builds were studied in both as-built and hot isostatically pressed conditions. The resultant complex microstructures were studied under scanning and transmission electron microscopes while their dynamic mechanical behavior was evaluated using a split-Hopkinson pressure bar testing system. Effects of initial porosity and microstructural evolution during HIP treatment on mechanical response are discussed.}, journal={Additive Manufacturing}, author={Gangireddy, Sindhura and Gwalani, Bharat and Liu, Kaimiao and Faierson, Eric J. and Mishra, Rajiv S.}, year={2019}, month={Mar}, pages={53–64} }
 @article{gwalani_gorsse_soni_carl_ley_smith_ayyagari_yufeng_young_mishra_et al._2019, title={Role of copper on L12 precipitation strengthened fcc based high entropy alloy}, volume={6}, DOI={10.1016/j.mtla.2019.100282}, abstractNote={A novel face-centered cubic (fcc)-based precipitation-hardenable high entropy alloy (HEA) or more broadly termed complex concentrated alloy (CCA) has been designed by coupling the beneficial effects of adding small amounts of Ti and Cu to the base alloy, Al0.3CoCrFeNi. While previous work has shown that large concentrations of Cu in fcc HEAs based on CoCrFeNi can lead to embrittlement, the present study clearly shows that in small amounts this alloying element can be quite beneficial, since Cu stabilizes the ordered L12 (gamma prime) phase, and acts as a heterogeneous nucleation site for this ordered phase within the fcc matrix. Additionally, Ti also stabilizes the L12 phase, increasing its volume fraction. This novel precipitation-hardened HEA/CCA, with a nominal composition of Al0.3Cu0.3Ti0.2CoCrFeNi, exhibits yield and ultimate tensile strengths of 820 MPa and 1100 MPa at room temperature respectively, while retaining a tensile ductility of nearly 20% and an extraordinarily high strain hardening rate ∼ 2700 MPa, a rather unique balance of properties for an fcc-based austenitic alloy.}, journal={Materialia}, author={Gwalani, Bharat and Gorsse, Stéphane and Soni, Vishal and Carl, Matthew and Ley, Nathen and Smith, Jesse and Ayyagari, Aditya V. and Yufeng, Zheng and Young, Marcus and Mishra, Rajiv S. and et al.}, year={2019}, month={Jun}, pages={100282} }
 @article{gwalani_gwalani_o'neill_mikler_banerjee_2019, title={Simulation of solute clusters in metallic systems}, volume={27}, DOI={10.1088/1361-651x/ab4b3d}, abstractNote={The arrangement of atoms in the microstructures of alloys plays a key role in defining their physical and functional properties. These microstructures are studied to detect deviations from the expected homogeneous distribution using frequency distribution tests and cluster detection algorithms on reconstructions obtained from atom probe microscopy. However, it is challenging to evaluate and validate the performance of these algorithms using the reconstructed data because of the experimental limitations of the atom probe data itself. Low detector efficiency and reconstructional artifacts may lead to loss of existing clusters, or introduce heterogeneities that do not reflect the original arrangement. Additionally, retrieving atom probe data is a time and cost-prohibitive process. These challenges call for the use of simulated datasets with known concentrations and distributions to evaluate algorithms that analyze distributions or detect clusters. In this paper, we extend the existing methodology to simulate the creation of solute clusters in very dilute solutions for any solution. We propose methods to create denser and wider clusters in any solution irrespective of the concentration. Three novel solute cluster simulation techniques incremental, hierarchical and gravitational clustering are presented and compared in this paper. The simulated datasets can be used to validate and compare the performance of frequency distribution or cluster discovery algorithms. We compare the cluster analysis results obtained from the single linkage algorithm and DBSCAN to highlight the utility of these datasets.}, number={8}, journal={Modelling and Simulation in Materials Science and Engineering}, author={Gwalani, Harsha and Gwalani, Bharat and O'Neill, Marty and Mikler, Armin R. and Banerjee, Rajarshi}, year={2019}, pages={085014} }
 @article{gwalani_pohan_waseem_alam_hong_ryu_banerjee_2019, title={Strengthening of Al0. 3CoCrFeMnNi-based ODS high entropy alloys with incremental changes in the concentration of Y2O3}, volume={162}, DOI={10.1016/j.scriptamat.2018.12.021}, abstractNote={The high-entropy alloy (HEA) composite Al0.3CoCrFeMnNi based on the face-centered-cubic (FCC) system and reinforced with 0–3 vol% Y2O3 was processed by mechanical alloying followed by spark plasma sintering (SPS). The compressive yield strength of the Al0.3CoCrFeMnNi high-entropy alloy (HEA) increased phenomenally, from 0.98 GPa (0 vol% Y2O3) to 1.76 GPa (3 vol% Y2O3). A quantitative analysis by atom probe tomography (APT) suggested the in-situ formation of complex oxide resulting from the reaction of Y2O3 with the HEA matrix during processing, enhancing the strength. Using the dispersion-barrier hardening model, the strengthening by dispersoids in Al0.3CoCrFeMnNi with Y2O3 was calculated, and closely matched the experimental results.}, journal={Scripta Materialia}, author={Gwalani, Bharat and Pohan, Rizaldy M. and Waseem, Owais Ahmed and Alam, Talukder and Hong, Soon Hyung and Ryu, Ho Jin and Banerjee, Rajarshi}, year={2019}, month={Mar}, pages={477–481} }
 @article{gwalani_gorsse_choudhuri_zheng_mishra_banerjee_2019, title={Tensile yield strength of a single bulk Al0. 3CoCrFeNi high entropy alloy can be tuned from 160 MPa to 1800 MPa}, volume={162}, DOI={10.1016/j.scriptamat.2018.10.023}, abstractNote={While there have been multiple recent reports in the literature of exceptional combinations of yield strength and ductility in high entropy alloys, there have been no reports discussing the extraordinary tunability of the mechanical properties in the same alloy in these systems. This paper shows that the tensile yield-strength of a single Al0.3CoCrFeNi high entropy alloy (or complex-concentrated alloy), can be enhanced from 160 MPa to over 1800 MPa (1.8 GPa), a 1025% increase, via microstructural engineering enabled by thermo-mechanical processing of the bulk alloy. Such strength variations for the same composition are unprecedented in any other class of alloys.}, journal={Scripta Materialia}, author={Gwalani, Bharat and Gorsse, Stephane and Choudhuri, Deep and Zheng, Yufeng and Mishra, Rajiv S. and Banerjee, Rajarshi}, year={2019}, month={Mar}, pages={18–23} }
 @inproceedings{chaudhary_borkar_mikler_gwalani_choudhuri_soni_alam_ramanujan_banerjee_2018, title={Additively Manufactured Functionally Graded FeNi based High Entropy Magnetic Alloys}, booktitle={2018 IEEE International Magnetics Conference (INTERMAG}, publisher={IEEE}, author={Chaudhary, V. and Borkar, T. and Mikler, C.V. and Gwalani, B. and Choudhuri, D. and Soni, V. and Alam, T. and Ramanujan, R.V. and Banerjee, R.}, year={2018} }
 @article{choudhuri_shukla_green_gwalani_ageh_banerjee_mishra_2018, title={Crystallographically degenerate B2 precipitation in a plastically deformed fcc-based complex concentrated alloy}, volume={6}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85041397841&partnerID=MN8TOARS}, DOI={10.1080/21663831.2018.1426649}, abstractNote={ABSTRACT Bcc-ordered B2 and fcc phases manifest three different orientation relationships (ORs) in the same microstructure: Kurdjumov–Sachs, Nishiyama–Wasserman and Pitsch. This unique microstructure was developed via conventional cold-rolling and subsequent annealing of an fcc-based Al0.3CoCrFeNi complex concentrated alloy (CCA). The degeneracy in crystallographic ORs was caused by {111}⟨112⟩twins, on multiple {111}, from the prior cold-rolling step. Annealing produced B2 precipitates on all the major fcc slip-systems by heterogeneously nucleating B2 at twin-matrix interfaces and twin–twin intersections. Such a precipitation-hardenable microstructure is expected to increase the strength of fcc-based CCAs by effectively blocking 1/2⟨110⟩and 1/6⟨112⟩mobile dislocations. Impact statement Three different fcc-B2 orientation relationships (ORs) were observed for the first time in complex concentrated alloys. Such degenerate ORs in B2 precipitation can potentially block dislocation on multiple slip planes. GRAPHICAL ABSTRACT}, number={3}, journal={Materials Research Letters}, author={Choudhuri, D. and Shukla, S. and Green, W.B. and Gwalani, B. and Ageh, V. and Banerjee, R. and Mishra, R.S.}, year={2018}, pages={171–177} }
 @article{alam_gwalani_viswanathan_fraser_banerjee_2018, title={Detailed Investigation of Core?Shell Precipitates in a Cu-Containing High Entropy Alloy}, volume={70}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85047802385&partnerID=MN8TOARS}, DOI={10.1007/s11837-018-2935-8}, number={9}, journal={JOM}, author={Alam, T. and Gwalani, B. and Viswanathan, G. and Fraser, H. and Banerjee, R.}, year={2018}, pages={1771–1775} }
 @article{gangireddy_gwalani_mishra_2018, title={Grain size dependence of strain rate sensitivity in a single phase FCC high entropy alloy Al0.3CoCrFeNi}, volume={736}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/j.msea.2018.09.009}, DOI={10.1016/j.msea.2018.09.009}, abstractNote={High-entropy alloys (HEAs) can offer exceptional strain-rate sensitivity (SRS) due to high lattice-friction and strong solid-solution strengthening, and in some cases, low stacking fault energy. In this study, SRS of a single phase FCC HEA- Al0.3CoCrFeNi was investigated at two grain sizes. Due to its outstanding Hall-Petch coefficient, grain size becomes a crucial microstructural feature in determination of strength and SRS. Change in SRS due to grain refinement was derived to be inversely proportional to associated strength gain, in coarse microstructures where grain size >> dislocation forest cell size. This correlation was proven using two microstructures with grain sizes of 12 µm and 150 µm, with yield strengths of 313 MPa and 145 MPa, and demonstrated SRS of m = 0.029 and 0.064, respectively. SRS was also derived to increase linearly with strength contribution from thermal short-range obstacles. The slope reflects the maximum upper limit on SRS possible upon elimination of all other obstacles of long-range nature. This limiting value of SRS was derived to be 0.118 for this HEA.}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Gangireddy, Sindhura and Gwalani, Bharat and Mishra, Rajiv S.}, year={2018}, pages={344–348} }
 @article{shukla_choudhuri_wang_liu_wheeler_williams_gwalani_mishra_2018, title={Hierarchical features infused heterogeneous grain structure for extraordinary strength-ductility synergy}, volume={6}, DOI={10.1080/21663831.2018.1538023}, abstractNote={ABSTRACT A synergistic balance of strength and ductility was achieved in a prototypical fcc-based Al0.3CoCrFeNi complex concentrated alloy by incorporating hierarchical microstructural features into heterogeneous grain structure. Microstructural hierarchy was composed of different morphologies and size-scales of B2 precipitates and nano-twins that were incorporated in parent fcc matrix, which, additionally, was comprised of domains of fine and coarse grains. Strain partitioning between refined and coarse grains produced geometrically necessary dislocations during plastic deformation. This facilitated long-range back stresses during further deformation leading to simultaneous enhancement of strength and ductility. Furthermore, B2 precipitates complemented back stress and increased inherent matrix strength. GRAPHICAL ABSTRACT IMPACT STATEMENT Architecting hierarchical microstructural features into a heterogeneous grain structured complex concentrated alloy avoided the classic strength-ductility trade-off paradigm.}, number={12}, journal={Materials Research Letters}, author={Shukla, Shivakant and Choudhuri, Deep and Wang, Tianhao and Liu, Kaimiao and Wheeler, Robert and Williams, Sarah and Gwalani, Bharat and Mishra, Rajiv S.}, year={2018}, pages={676–682} }
 @article{gwalani_pohan_lee_lee_banerjee_ryu_hong_2018, title={High-entropy alloy strengthened by in situ formation of entropy-stabilized nano-dispersoids}, volume={8}, ISSN={2045-2322}, DOI={10.1038/s41598-018-32552-6}, abstractNote={Abstract}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Gwalani, Bharat and Pohan, Rizaldy M. and Lee, Junho and Lee, Bin and Banerjee, Rajarshi and Ryu, Ho Jin and Hong, Soon Hyung}, year={2018}, month={Sep}, pages={14085} }
 @article{chaudhary_gwalani_soni_ramanujan_banerjee_2018, title={Influence of Cr Substitution and Temperature on Hierarchical Phase Decomposition in the AlCoFeNi High Entropy Alloy}, volume={8}, ISSN={2045-2322}, DOI={10.1038/s41598-018-33922-w}, abstractNote={Abstract}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Chaudhary, V. and Gwalani, B. and Soni, V. and Ramanujan, R. V. and Banerjee, R.}, year={2018}, month={Oct}, pages={15578} }
 @article{soni_senkov_gwalani_miracle_banerjee_2018, title={Microstructural Design for Improving Ductility of An Initially Brittle Refractory High Entropy Alloy}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85048431301&partnerID=MN8TOARS}, DOI={10.1038/s41598-018-27144-3}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, author={Soni, V. and Senkov, O.N. and Gwalani, B. and Miracle, D.B. and Banerjee, R.}, year={2018} }
 @article{gangireddy_kaimiao_gwalani_mishra_2018, title={Microstructural dependence of strain rate sensitivity in thermomechanically processed Al<inf>0.1</inf>CoCrFeNi high entropy alloy}, volume={727}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046625533&partnerID=MN8TOARS}, DOI={10.1016/j.msea.2018.04.108}, abstractNote={Al0.1CoCrFeNi is a single-phase FCC high entropy alloy (HEA) that promises remarkable work-hardening due to its low stacking fault energy (SFE) resulting in suppression of cross-slip and dynamic recovery. The cast material of low yield strength was cold-worked to enhance strength; and then subjected to recovery and recrystallization treatments to improve ductility. Mechanical responses from standard tensile testing at quasi-static strain rate of 10−3 s−1 were coupled with dynamic deformation from split-Hopkinson pressure bar (SHPB) testing at 103 s−1 to study strain rate sensitivity (SRS) and its microstructural dependence in various conditions generated by thermomechanical processing. While dynamic work-hardening remained high in all microstructural conditions, SRS was highly sensitive to the nature of obstacles in each condition. The cast condition showed a moderate SRS of 0.017, but introduction of dislocation tangles and large deformation twins with cold work rendered a sharp drop in SRS to ~ 0. As the density of these defects is reduced during low-temperature annealing treatments, the recovered microstructures showed SRS recuperating back to original SRS level of 0.017. Higher temperature treatments resulted in partial recrystallization and lower SRS < 0.008 due to additional athermal strength contribution from grain refinement in the recrystallized portions and remnant cold work in unrecrystallized portions. Dynamic work-hardening remained very high at ~ 1600 MPa in all conditions from a combination of dynamic recovery suppression and intense twinning that is inherent to the HEA from its low SFE.}, journal={Materials Science and Engineering A}, author={Gangireddy, S. and Kaimiao, L. and Gwalani, B. and Mishra, R.}, year={2018}, pages={148–159} }
 @article{tungala_arora_gwalani_mishra_brennan_cho_2018, title={Microstructure and mechanical properties of friction stir processed cast Eglin steel (ES-1)}, volume={709}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85031787425&partnerID=MN8TOARS}, DOI={10.1016/j.msea.2017.10.033}, abstractNote={Eglin steel, an ultra-high-strength steel developed for various demanding applications, is a low-cost alternative to 4340 steel, in which nickel and cobalt additions are replaced by higher tungsten additions, thereby achieving comparable strength and ductility. Friction stir processing (FSP) was carried out on this steel under two heat input conditions, which fell above the A3 transformation line. Microhardness values along the horizontal and vertical directions of the processed region cross section were reported for the lower heat input condition, and correlated with corresponding microstructures. A 3D heat transfer and material flow model was used to predict the peak temperature and cooling rates in these zones. Site-specific tensile tests of specimens extracted from the top to the bottom of the stir zone (SZ) showed ultimate tensile strength (UTS) greater than 2 GPa, with a total elongation close to 10% at ~ 4 mm from the top surface of SZ. Transmission electron microscopy (TEM) analysis of the high strength location showed microstructure consisting of nano-twinned martensite and nano-bainite laths of size ranging from 200 nm to 300 nm, and confirmed the existence of retained austenite. This mixed microstructure was comprised of finer aggregates of martensite, bainite and retained austenite, which were postulated to be responsible for the high strength and ductility combinations.}, journal={Materials Science and Engineering A}, author={Tungala, V. and Arora, A. and Gwalani, B. and Mishra, R.S. and Brennan, R.E. and Cho, K.C.}, year={2018}, pages={105–114} }
 @article{gwalani_ayyagari_choudhuri_scharf_mukherjee_gibson_banerjee_2018, title={Microstructure and wear resistance of an intermetallic-based Al0.25Ti0.75CoCrFeNi high entropy alloy}, volume={210}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85020886295&partnerID=MN8TOARS}, DOI={10.1016/j.matchemphys.2017.06.034}, abstractNote={An Al0.25Ti0.75CoCrFeNi high entropy alloy (HEA), consisting of multiple principal elements, forms the uncommonly observed chi-phase, which is a large lattice parameter intermetallic phase based on the body centered cubic crystal structure, as the matrix phase and a L21 phase (ordered Huesler phase, X2YZ-type based on the face-centered cubic structure) as a major secondary phase. Additionally, a face centered cubic phase with a high density of nano-twins is also present in the microstructure as a third phase. The extremely high Vicker's hardness of the matrix chi phase (1090Hv ± 14) and of the L21 phase (570 ± 9 HV) along with low sliding coefficient of friction (∼0.3) and low wear rate (∼1.2 × 10−5 mm3/N m) makes this HEA a promising candidate for mechanical wear-resistant applications.}, journal={Materials Chemistry and Physics}, author={Gwalani, B. and Ayyagari, A.V. and Choudhuri, D. and Scharf, T. and Mukherjee, S. and Gibson, M. and Banerjee, R.}, year={2018}, pages={197–206} }
 @article{pohan_gwalani_lee_alam_hwang_ryu_banerjee_hong_2018, title={Microstructures and mechanical properties of mechanically alloyed and spark plasma sintered Al<inf>0.3</inf>CoCrFeMnNi high entropy alloy}, volume={210}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85029534341&partnerID=MN8TOARS}, DOI={10.1016/j.matchemphys.2017.09.013}, abstractNote={The present study focuses on phase evolution in Al0.3CoCrFeMnNi high entropy alloys (HEAs) during mechanical alloying and after spark plasma sintering. Aluminium addition hardens and induces ordered precipitates in a soft fcc alloy based on CoCrFeMnNi. Mechanical alloying of the alloy powders resulted in a single fcc phase. However, ordered B2 precipitates and chromium carbide precipitates were observed after spark plasma sintering. Sintering temperature optimization was done and maximum densification and hardness were obtained at 900 °C. High compressive yield strength of 979 ± 20 MPa and compressive ductility of 39 ± 3% were observed for the SPS processed alloy. Significant contributions from grain boundary strengthening coupled with dispersion strengthening via carbides and B2 particles appear to be major contributors to alloy strengthening. These hard intermetallic particles not only keep the grain growth in check but also increase the cumulative (fcc + B2) strength of the material.}, journal={Materials Chemistry and Physics}, author={Pohan, R.M. and Gwalani, B. and Lee, J. and Alam, T. and Hwang, J.Y. and Ryu, H.J. and Banerjee, R. and Hong, S.H.}, year={2018}, pages={62–70} }
 @article{gangireddy_gwalani_liu_banerjee_mishra_2018, title={Microstructures with extraordinary dynamic work hardening and strain rate sensitivity in Al<inf>0.3</inf>CoCrFeNi high entropy alloy}, volume={734}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85050678539&partnerID=MN8TOARS}, DOI={10.1016/j.msea.2018.07.088}, abstractNote={Al0.3CoCrFeNi is an FCC-based high entropy alloy (HEA) that can display a wide spectrum of mechanical properties. Cold work and precipitation are good strengthening mechanisms in this HEA, and their effect on dynamic work hardening and strain rate sensitivity (SRS) was investigated. Dynamic deformation testing using split-Hopkinson pressure bar (SHPB) at 2 × 103 s−1 and quasistatic tensile deformation at 10−3 s−1 were conducted on thermomechanically processed conditions. The HEA behaved like a conventional FCC alloy with higher flow tresses and work hardening in the dynamic regime. All the conditions showed substantial dynamic work hardening due to the low stacking fault energy (SFE) of the HEA. Precipitates enhanced twinning, as observed from post-SHPB deformed microstructures, and resulted in an extraordinary work hardening rate > 2200 MPa. Cold work introduced large-scale deformation twins and these suppressed further twin nucleation during testing, and a lower work hardening of 1000 MPa was observed. SRS was highly microstructure-sensitive and varied from an exceptional m = 0.063 in the cast condition, where the biggest flow stress contributor is solute strengthening of short-range nature and can be thermally activated. Introduction of long-range athermal incoherent precipitates reduced SRS slightly. Cold work, which introduces much higher density of athermal defects, dislocations and large-scale deformation twins, drastically reduced SRS to m = 0.006. Upon annealing the rolled material, partial recovery of cold work and precipitation occurred together and coupled to result in a moderate SRS, m= 0.02.}, journal={Materials Science and Engineering A}, author={Gangireddy, S. and Gwalani, B. and Liu, K. and Banerjee, R. and Mishra, R.S.}, year={2018}, pages={42–50} }
 @article{gwalani_gorsse_choudhuri_styles_zheng_mishra_banerjee_2018, title={Modifying transformation pathways in high entropy alloys or complex concentrated alloys via thermo-mechanical processing}, volume={153}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85047019231&partnerID=MN8TOARS}, DOI={10.1016/j.actamat.2018.05.009}, abstractNote={Often the experimentally-observed, single-phase high entropy alloy (HEA) is the result of second-phase precipitation constrained by thermodynamic and kinetic factors. Using Al0.3CoCrFeNi as a candidate HEA, this paper demonstrates the strong influence of thermo-mechanical processing on the transformation pathway adopted for isothermal second-phase precipitation. A traditional thermo-mechanical processing route comprised of homogenization cold-rolling solution treatment in the single fcc phase region, followed by a precipitation anneal at a lower temperature, results in a homogeneous distribution of nanometer scale-ordered L12 (gamma prime-like) precipitates within the fcc matrix. In contrast, if cold-rolling is followed directly by annealing at the precipitation temperature, then the resulting microstructural evolution pathway changes completely, with concurrent recrystallization of the matrix fcc grains and precipitation of B2 and sigma phases, largely at the grain boundaries. These experimentally observed variations in transformation pathway have been rationalized via the competition between the thermodynamic driving force and activation barrier for second-phase nucleation in this alloy, coupled with the kinetics of the process. The microstructural variations that result from these dramatically different phase transformation pathways can lead to some rather exceptional mechanical properties that can be varied over a large range even for a single Al0.3CoCrFeNi HEA composition.}, journal={Acta Materialia}, author={Gwalani, B. and Gorsse, S. and Choudhuri, D. and Styles, M. and Zheng, Y. and Mishra, R.S. and Banerjee, R.}, year={2018}, pages={169–185} }
 @article{soni_gwalani_senkov_viswanathan_alam_miracle_banerjee_2018, title={Phase stability as a function of temperature in a refractory high-entropy alloy}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85049941455&partnerID=MN8TOARS}, DOI={10.1557/jmr.2018.223}, abstractNote={Abstract}, journal={Journal of Materials Research}, author={Soni, V. and Gwalani, B. and Senkov, O.N. and Viswanathan, B. and Alam, T. and Miracle, D.B. and Banerjee, R.}, year={2018}, pages={1–12} }
 @article{ayyagari_barthelemy_gwalani_banerjee_scharf_mukherjee_2018, title={Reciprocating sliding wear behavior of high entropy alloys in dry and marine environments}, volume={210}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85023620006&partnerID=MN8TOARS}, DOI={10.1016/j.matchemphys.2017.07.031}, abstractNote={The reciprocating sliding wear behavior of two high entropy alloys, CoCrFeMnNi and Al0.1CoCrFeNi, was evaluated in dry and marine environments. Both the alloys showed better wear performance in marine environment as compared to dry condition, indicating negative synergy of wear and corrosion. Al0.1CoCrFeNi was more wear resistant compared to CoCrFeMnNi in both environments. Accelerated electrochemical corrosion tests were carried out to quantify the effect of passive layer on marine wear behavior. Al0.1CoCrFeNi showed lower corrosion rate, higher pitting resistance and greater degree of passivation. A strong correlation was found between the electrochemical polarization resistance and wear resistance.}, journal={Materials Chemistry and Physics}, author={Ayyagari, A. and Barthelemy, C. and Gwalani, B. and Banerjee, R. and Scharf, T.W. and Mukherjee, S.}, year={2018}, pages={162–169} }
 @article{ayyagari_gwalani_muskeri_mukherjee_banerjee_2018, title={Surface degradation mechanisms in precipitation-hardened high-entropy alloys}, volume={2}, ISSN={2397-2106}, DOI={10.1038/s41529-018-0054-1}, abstractNote={Abstract}, journal={npj Materials Degradation}, publisher={Springer Science and Business Media LLC}, author={Ayyagari, Aditya V. and Gwalani, Bharat and Muskeri, Saideep and Mukherjee, Sundeep and Banerjee, Rajarshi}, year={2018}, month={Oct}, pages={33} }
 @article{kuang_was_miller_kaufman_alam_gwalani_banerjee_2018, title={The effect of cold rolling on grain boundary structure and stress corrosion cracking susceptibility of twins in alloy 690 in simulated PWR primary water environment}, volume={130}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85033383873&partnerID=MN8TOARS}, DOI={10.1016/j.corsci.2017.11.002}, abstractNote={The effects of cold rolling on the structure and stress corrosion cracking (SCC) susceptibility of twin boundaries in alloy 690 were studied. Most of the twin boundaries were transformed into random high angle boundaries (RHABs) following cold rolling. The transformed twin boundaries (TTBs) showed increased susceptibility to carbide precipitation during subsequent aging at 475 °C. The SCC initiation test in 360 °C hydrogenated water indicated that the prior RHABs exhibited increased SCC susceptibility after cold rolling. Moreover, TTBs become susceptible to SCC due to the promoted outward diffusion of Cr and can enhance the connectivity of susceptible grain boundaries.}, journal={Corrosion Science}, author={Kuang, W. and Was, G.S. and Miller, C. and Kaufman, M. and Alam, T. and Gwalani, B. and Banerjee, R.}, year={2018}, pages={126–137} }
 @article{borkar_chaudhary_gwalani_choudhuri_mikler_soni_alam_v. ramanujan_banerjee_2017, title={A Combinatorial Approach for Assessing the Magnetic Properties of High Entropy Alloys: Role of Cr in AlCo<inf>x</inf>Cr<inf>1?x</inf>FeNi}, volume={19}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85019862302&partnerID=MN8TOARS}, DOI={10.1002/adem.201700048}, abstractNote={A combinatorial assessment of composition‐microstructure‐magnetic property relationships in magnetic high entropy AlCoxCr1‐xFeNi alloy (0 ≤ x ≤ 1) system has been carried out using compositionally graded alloys fabricated via laser additive manufacturing. At one end, the AlCoFeNi composition (x = 1) consisted of equiaxed B2 grains, exhibiting very early stages of phase separation (only compositional partitioning) into Ni–Al rich and Fe–Co rich regions within grains of the B2 phase. At the other extreme, the AlCrFeNi composition (x = 0) exhibited grains with pronounced spinodal decomposition, resulting in a B2 + bcc microstructure with the degree of spinodal decomposition progressively increasing with Cr content in these AlCoxCr1–xFeNi alloys. While the saturation magnetization (Ms) monotonically increases six times from x = 0 to x = 1, the coercivity (Hc) variation is non‐monotonic, increasing seven times from x = 0 to x = 0.4, and subsequently decreasing fourteen times from x = 0.4 to x = 1.0. The magnetic phase transition temperature (Tc) for these alloys also increases monotonically with increasing Co content with a second phase transition exhibited in a certain range of compositions between x = 0.6 to x = 0.8. Such substantial changes in the magnetization behavior and properties of magnetic high entropy systems opens possibilities of tuning these alloys for specific soft or hard magnetic component applications.}, number={8}, journal={Advanced Engineering Materials}, author={Borkar, T. and Chaudhary, V. and Gwalani, B. and Choudhuri, D. and Mikler, C.V. and Soni, V. and Alam, T. and V. Ramanujan, R. and Banerjee, R.}, year={2017} }
 @article{choudhuri_gwalani_gorsse_mikler_ramanujan_gibson_banerjee_2017, title={Change in the primary solidification phase from fcc to bcc-based B2 in high entropy or complex concentrated alloys}, volume={127}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84991108142&partnerID=MN8TOARS}, DOI={10.1016/j.scriptamat.2016.09.023}, abstractNote={An examination of a compositionally graded AlxCuCrFeNi2 high entropy alloy (HEA) or complex concentrated alloy (CCA), revealed that marginally increasing Al content from x = 0.8 to x = 1.0 (+ 6 at.%) changes the primary solidification phase from a simple disordered-fcc to a bcc-based ordered-B2 phase. Subsequently, a second solidification product forms, a disordered-bcc in case of x = 0.8 and a disordered-fcc in case of x = 1.0. Solid-state decomposition within these phases results in fcc + L12 and bcc + B2 products, accompanied by compositional partitioning. These results provide new insights into the influence of Al on the primary solidification product, and have been rationalized using a computational thermodynamic approach.}, journal={Scripta Materialia}, author={Choudhuri, D. and Gwalani, B. and Gorsse, S. and Mikler, C.V. and Ramanujan, R.V. and Gibson, M.A. and Banerjee, R.}, year={2017}, pages={186–190} }
 @article{gwalani_choudhuri_soni_ren_styles_hwang_nam_ryu_hong_banerjee_2017, title={Cu assisted stabilization and nucleation of L1<inf>2</inf>precipitates in Al<inf>0.3</inf>CuFeCrNi<inf>2</inf>fcc-based high entropy alloy}, volume={129}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85014687888&partnerID=MN8TOARS}, DOI={10.1016/j.actamat.2017.02.053}, abstractNote={A detailed investigation of precipitation of the ordered L12 (γ′) phase in a Al0.3CrCuFeNi2 high entropy alloy (HEA), more generally referred to as a complex concentrated alloy (CCA), reveals the role of copper (Cu) on stabilization and precipitation of the ordered L12 (γ′) phase. Detailed characterization via coupling of scanning and transmission electron microscopy, and atom probe tomography revealed novel insights into Cu clustering within the face-centered cubic matrix of this HEA, leading to heterogeneous nucleation sites for the γ′ precipitates. The subsequent partitioning of Cu into the γ′ precipitates indicates their stabilization is due to Cu addition. The γ′ order-disorder transition temperature was determined to be ∼930 °C in this alloy, based on synchrotron diffraction experiments, involving in situ annealing. The growth and high temperature stability of the γ′ precipitates was also confirmed via systematic scanning electron microscopy investigations of samples annealed at temperatures in the range of 700–900 °C. The role of Cu revealed by this study can be employed in the design of precipitation strengthened HEAs, as well as in a more general sense applied to other types of superalloys, with the objective of potentially enhancing their mechanical properties at room and elevated temperatures.}, journal={Acta Materialia}, author={Gwalani, B. and Choudhuri, D. and Soni, V. and Ren, Y. and Styles, M. and Hwang, J.Y. and Nam, S.J. and Ryu, H. and Hong, S.H. and Banerjee, R.}, year={2017}, pages={170–182} }
 @article{patel_cha_kang_gwalani_choi_2017, title={High performance rechargeable Li-S batteries using binder-free large sulfur-loaded three-dimensional carbon nanotubes}, volume={118}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015436503&partnerID=MN8TOARS}, DOI={10.1016/j.carbon.2017.03.035}, abstractNote={The increasing demand for clean and efficient energy storage in portable electronics, electric vehicles, and smart energy grid has spurred attention to develop advanced battery systems. Complementing the high theoretical specific capacity of sulfur cathode (∼1672 mAh/g), environmentally benign, and low-cost, Li-S batteries can meet the myriad needs of inexpensive and high energy density energy storage. However, the intrinsic drawbacks of poor cycle life and low charge efficiency in conventional Li-S batteries hinder the advancement of this alluring technology. Here, we propose a novel and facile synthesis of binder-free three-dimensional carbon nanotubes (3D CNTs)/sulfur (S) hybrid composite as an electrode material, where 3D CNTs provide a high conduction path and short diffusion length for Li-ions, while confining soluble poly-sulfides within the structure for high cycling performance. The unique binder free cathode design results in one of the highest sulfur loading of 8.33 mg/cm2 (∼55 wt% S in the cathode electrode) with excellent areal and specific capacity of 8.89 mAh/cm2 and 1068 mAh/g at 0.1C rate (∼1.4 mA/cm2) offering coulombic efficiency of greater than 95% for 150 cycles. The novel cell exhibits maximum specific energy of ∼1233 Wh/kg with a specific power of ∼476 W/kg, with respect to the mass of the cathode.}, journal={Carbon}, author={Patel, M.D. and Cha, E. and Kang, C. and Gwalani, B. and Choi, W.}, year={2017}, pages={120–126} }
 @article{gwalani_soni_lee_mantri_ren_banerjee_2017, title={Optimizing the coupled effects of Hall-Petch and precipitation strengthening in a Al<inf>0.3</inf>CoCrFeNi high entropy alloy}, volume={121}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85013765881&partnerID=MN8TOARS}, DOI={10.1016/j.matdes.2017.02.072}, abstractNote={A successful demonstration of applying integrated strengthening using Hall-Petch strengthening (grains size effect) and precipitation strengthening is shown in the fcc based high entropy alloy (HEA) Al0.3CoCrFeNi, leading to quantitative determinations of the Hall-Petch coefficients for both hardness and tensile yield strength, as well as the enhancements in the yield strength from two distinct types of ordered precipitates, L12 and B2. An excellent combination of yield strength (~ 490 MPa), ultimate tensile strength (~ 850 MPa), and ductility (~ 45% elongation) was achieved by optimizing and coupling both strengthening mechanisms, resulting from a refined grain size as well as both L12 and B2 ordered precipitates. This opens up new avenues for the future development of HEAs, with the appropriate balance of properties required for engineering applications.}, journal={Materials and Design}, author={Gwalani, B. and Soni, V. and Lee, M. and Mantri, S.A. and Ren, Y. and Banerjee, R.}, year={2017}, pages={254–260} }
 @article{hendrickson_mantri_ren_alam_soni_gwalani_styles_choudhuri_banerjee_2017, title={The evolution of microstructure and microhardness in a biomedical Ti?35Nb?7Zr?5Ta alloy}, volume={52}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84997840776&partnerID=MN8TOARS}, DOI={10.1007/s10853-016-0591-3}, number={6}, journal={Journal of Materials Science}, author={Hendrickson, M. and Mantri, S.A. and Ren, Y. and Alam, T. and Soni, V. and Gwalani, B. and Styles, M. and Choudhuri, D. and Banerjee, R.}, year={2017}, pages={3062–3073} }
 @article{mikler_chaudhary_soni_gwalani_ramanujan_banerjee_2017, title={Tuning the phase stability and magnetic properties of laser additively processed Fe-30at%Ni soft magnetic alloys}, volume={199}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85017507873&partnerID=MN8TOARS}, DOI={10.1016/j.matlet.2017.04.054}, abstractNote={The widely used soft-magnetic alloy, Fe-30at%Ni, has been deposited using laser engineered net shaping (LENS™). A range of laser powers and travel speeds have been studied and correlated to phase stability and magnetic properties of the alloy. Columnar grains of the metastable fcc phase are predominant for slower travel speeds, however with increasing travel speeds, a substantial volume-fraction of a bcc, possibly martensitic, phase was observed. The bcc dominated microstructures exhibit a substantially higher saturation magnetization (Ms) compared to the fcc dominated microstructures.}, journal={Materials Letters}, author={Mikler, C.V. and Chaudhary, V. and Soni, V. and Gwalani, B. and Ramanujan, R.V. and Banerjee, R.}, year={2017}, pages={88–92} }
 @article{borkar_gwalani_choudhuri_mikler_yannetta_chen_ramanujan_styles_gibson_banerjee_2016, title={A combinatorial assessment of Al<inf>x</inf>CrCuFeNi<inf>2</inf>(0 < x < 1.5) complex concentrated alloys: Microstructure, microhardness, and magnetic properties}, volume={116}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84975482536&partnerID=MN8TOARS}, DOI={10.1016/j.actamat.2016.06.025}, abstractNote={This article discusses a novel combinatorial approach for assessing composition-microstructure-microhardness-magnetic property relationships, using laser deposited compositionally graded AlxCrCuFeNi2 (0 < x < 1.5) complex concentrated alloys as a candidate system. The composition gradient has been achieved from CrCuFeNi2 to Al1.5CrCuFeNi2 over a length of ∼25 mm, deposited using the laser engineered net shaping process from a blend of elemental powders. With increasing Al content, there was a gradual change from a fcc-based microstructure (including the ordered L12 phase) to a bcc-based microstructure (including the ordered B2 phase), accompanied with an increase in microhardness. Interestingly, with increasing paramagnetic Al content, saturation magnetization as well as coercivity increases and reaches a maximum value when x = 1.3, indicating the tunability of magnetic properties by a paramagnetic element in this alloy system. Such graded alloys are highly attractive candidates for investigating the influence of systematic compositional changes on microstructural evolution and concurrent physical and mechanical properties in complex concentrated alloys or high entropy alloys.}, journal={Acta Materialia}, author={Borkar, T. and Gwalani, B. and Choudhuri, D. and Mikler, C.V. and Yannetta, C.J. and Chen, X. and Ramanujan, R.V. and Styles, M.J. and Gibson, M.A. and Banerjee, R.}, year={2016}, pages={63–76} }
 @article{gwalani_alam_miller_rojhirunsakool_kim_kim_kaufman_ren_banerjee_2016, title={Experimental investigation of the ordering pathway in a Ni-33 at.%Cr alloy}, volume={115}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84975299282&partnerID=MN8TOARS}, DOI={10.1016/j.actamat.2016.06.014}, abstractNote={The present study involves a detailed experimental investigation of the concurrent compositional clustering and long-range ordering tendencies in a Ni-33 at.%Cr alloy, carried out by coupling synchrotron-based X-ray diffraction (XRD), transmission electron microscopy (TEM), and atom probe tomography (APT). Synchrotron-based XRD results clearly exhibited progressively increasing lattice contraction in the matrix with increasing isothermal aging time, at 475 °C, eventually leading to the development of long-range ordering (LRO) of the Pt2Mo-type. Detailed TEM and APT investigations revealed that this LRO in the matrix is manifested in the form of nanometer-scale ordered domains, and the spatial distribution, size, morphology and compositional evolution of these domains have been carefully investigated. APT results also revealed the early stages of compositional clustering prior to the onset of long-range ordering in this alloy and such compositional clustering can potentially be correlated to the lattice contraction and previously proposed short-range ordering tendencies.}, journal={Acta Materialia}, author={Gwalani, B. and Alam, T. and Miller, C. and Rojhirunsakool, T. and Kim, Y.S. and Kim, S.S. and Kaufman, M.J. and Ren, Y. and Banerjee, R.}, year={2016}, pages={372–384} }
 @article{borkar_gwalani_choudhuri_alam_mantri_gibson_banerjee_2016, title={Hierarchical multi-scale microstructural evolution in an as-cast Al<inf>2</inf>CuCrFeNi<inf>2</inf>complex concentrated alloy}, volume={71}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84953790130&partnerID=MN8TOARS}, DOI={10.1016/j.intermet.2015.12.013}, abstractNote={The hierarchical evolution of the microstructure in an as-cast Al2CuCrFeNi2 alloy, across multiple length scales, was investigated by coupling scanning and transmission electron microscopy and atom probe tomography. This cast alloy undergoes a univariant eutectic dendritic solidification, which gives rise to a two-phase mixture of B2e (ordered BCC) and βe (disordered BCC) phases. The B2e phase forms a continuous matrix with the βe, being the minor phase, having a rod-like morphology. The B2e phase is further decomposed into B2f, Cu-plates, Cu-globules, and a small volume fraction of (Fe,Cr)-rich disordered βf2 regions. The βe phase further decomposed into Cu/B2s core/shell composite particles, where an ordered B2s shell surrounds a Cu-rich core. Most likely these Cu-rich cores act as heterogeneous nucleation sites for the B2s precipitates within the βf phase. This complex multi-scale decomposition process results in an intricate mixture of ordered and disordered solid solution phases.}, journal={Intermetallics}, author={Borkar, T. and Gwalani, B. and Choudhuri, D. and Alam, T. and Mantri, A.S. and Gibson, M.A. and Banerjee, R.}, year={2016}, pages={31–42} }
 @article{zhang_alam_gwalani_rong_banerjee_peng_nie_birbilis_2016, title={On the role of Ag in enhanced age hardening kinetics of Mg?Gd?Ag?Zr alloys}, volume={96}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84976347070&partnerID=MN8TOARS}, DOI={10.1080/09500839.2016.1190040}, abstractNote={Abstract The addition of Ag to the age hardenable Mg–Gd–Zr alloy system dramatically enhances early stage age hardening kinetics. Using atom probe tomography (APT), Ag-rich clusters were detected in a Ag-containing Mg–Gd–Zr alloy immediately after solution treatment and water quenching. During subsequent isothermal ageing at 200 °C, a high density of basal precipitates was observed during the early stages of ageing. These basal precipitates were enriched with Ag and Gd, as confirmed by APT. It is posited that Ag-rich clusters in the context of quenched-in vacancies can attract Gd atoms, increasing diffusion kinetics to facilitate the formation of the Ag + Gd-rich basal precipitates. The rapid formation of Ag + Gd-rich precipitates was responsible for accelerated ageing.}, number={6}, journal={Philosophical Magazine Letters}, author={Zhang, Y. and Alam, T. and Gwalani, B. and Rong, W. and Banerjee, R. and Peng, L.-M. and Nie, J.-F. and Birbilis, N.}, year={2016}, pages={212–219} }
 @article{xia_kang_patel_cai_gwalani_banerjee_shi_choi_2016, title={Pine Wood Extracted Activated Carbon through Self-Activation Process for High-Performance Lithium-Ion Battery}, volume={1}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85013154573&partnerID=MN8TOARS}, DOI={10.1002/slct.201600926}, abstractNote={Abstract}, number={13}, journal={ChemistrySelect}, author={Xia, C. and Kang, C. and Patel, M.D. and Cai, L. and Gwalani, B. and Banerjee, R. and Shi, S.Q. and Choi, W.}, year={2016}, pages={4000–4007} }
 @article{gwalani_soni_choudhuri_lee_hwang_nam_ryu_hong_banerjee_2016, title={Stability of ordered L1<inf>2</inf>and B<inf>2</inf>precipitates in face centered cubic based high entropy alloys - Al<inf>0.3</inf>CoFeCrNi and Al<inf>0.3</inf>CuFeCrNi<inf>2</inf>}, volume={123}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84976276936&partnerID=MN8TOARS}, DOI={10.1016/j.scriptamat.2016.06.019}, abstractNote={Adding a small amount of Al to the well-known high entropy alloy (HEA), Al0.1CoCrFeNi, to form Al0.3CoCrFeNi, leads to the precipitation of highly refined ordered L12 precipitates, which are stable at 550 °C. However, the L12 precipitates (stoichiometry of (Ni,Cr)3(Al,Fe,Co)) are de-stabilized and replaced by coarser B2 precipitates on annealing at 700 °C. Contrastingly, in the Co-free, Al0.3CuCrFeNi2 high entropy alloy, the L12 precipitates are stable at both 550 °C (~ 5 nm) and 700 °C (~ 50 nm), and exhibit a stoichiometry of (Ni,Cu)3(Al,Fe,Cr). These results lead to interesting insights into the stability of ordered phases in HEAs as a function of composition and temperature.}, journal={Scripta Materialia}, author={Gwalani, B. and Soni, V. and Choudhuri, D. and Lee, M. and Hwang, J.Y. and Nam, S.J. and Ryu, H. and Hong, S.H. and Banerjee, R.}, year={2016}, pages={130–134} }
 @inproceedings{kuang_miller_kaufman_alam_gwalani_banerjee_was_2015, title={Effects of cold work and aging treatments on the microstructure and stress corrosion cracking initiation behavior of solution annealed alloy 690}, booktitle={Proceedings of the 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems—Water Reactors}, author={Kuang, Wenjun and Miller, Cody and Kaufman, Mike and Alam, Talukder and Gwalani, Bharat and Banerjee, Rajarshi and Was, Gary S.}, year={2015} }
 @article{choudhuri_alam_borkar_gwalani_mantri_srinivasan_gibson_banerjee_2015, title={Formation of a Huesler-like L2<inf>1</inf>phase in a CoCrCuFeNiAlTi high-entropy alloy}, volume={100}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84923082556&partnerID=MN8TOARS}, DOI={10.1016/j.scriptamat.2014.12.006}, abstractNote={Ordered L21 Huesler phases not only exhibit interesting magnetic properties but are also known to substantially enhance creep resistance in multi-phase alloys. We present experimental evidence of a Huesler-like ordered L21 phase in a multicomponent High Entropy Alloy (HEA) and rationalize the titanium induced stabilization of this phase based on first-principles calculations. More broadly, this paper directly shows that the composition of HEAs can be tuned to obtain the desired microstructure, and potentially tailor their properties.}, journal={Scripta Materialia}, author={Choudhuri, D. and Alam, T. and Borkar, T. and Gwalani, B. and Mantri, A.S. and Srinivasan, S.G. and Gibson, M.A. and Banerjee, R.}, year={2015}, pages={36–39} }