@article{christudasjustus_felde_witharamage_esquivel_darwish_winkler_gupta_2023, title={Age-hardening behavior, corrosion mechanisms, and passive film structure of nanocrystalline Al-V supersaturated solid solution}, volume={135}, ISSN={["1941-1162"]}, url={https://doi.org/10.1016/j.jmst.2022.06.044}, DOI={10.1016/j.jmst.2022.06.044}, abstractNote={The effect of age-hardening on microstructure, hardness, and corrosion of an Al-5at.%V alloy, produced using high-energy ball milling and subsequent cold compaction, has been investigated. The alloy exhibited a grain size below 100 nm and extremely high solid solubility of V in Al (3.1 at.%). The age-hardening was carried out at 150, 200, and 250 °C. The peak-aged condition of 150 °C demonstrated the highest hardness—transpired from grain refinement, precipitation, and solid solution hardening. The corrosion resistance of the Al-5at.%V alloy was studied as a function of aging conditions. The peak-aged condition retained the corrosion resistance while it deteriorated in the over-aged condition. Nonetheless, the corrosion resistance of the ball-milled Al alloys in all the aging conditions was superior to that of pure Al. The passive film structure and origin of corrosion were studied using scanning/transmission electron microscopy (S/TEM). The high corrosion resistance of the alloy was attributed to the V enrichment at the film/metal interface and deposition of V on the cathodic phases, which suppresses the dissolution of Al within the pit and therefore promotes repassivation in the early stages of corrosion.}, journal={JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY}, author={Christudasjustus, J. and Felde, M. R. and Witharamage, C. S. and Esquivel, J. and Darwish, A. . A. . and Winkler, C. and Gupta, R. K.}, year={2023}, month={Feb}, pages={1–12} }
 @article{witharamage_darwish_christudasjustus_soltis_gupta_2023, title={Time-Dependent Corrosion Behavior of Aluminum Using Advanced Electrochemical and Characterization Techniques}, volume={170}, ISSN={["1945-7111"]}, url={https://doi.org/10.1149/1945-7111/acfb40}, DOI={10.1149/1945-7111/acfb40}, abstractNote={
 The time-dependent corrosion behavior of pure aluminum (Al) in a chloride-containing environment was investigated using various electrochemical and characterization techniques for up to 336 hours. Transmission electron microscopic and secondary ion mass spectroscopic analysis revealed the continuous dissolution of the surface film over the immersion time. In the meantime, the increasing passive oxide thickness resulted in the surface film resistance enhancement over the immersion time, as indicated by the electrochemical impedance spectroscopic analysis. The electrochemical noise measurements showed an increase in the corrosion kinetics with immersion time until 60 hours because of the accelerated localized corrosion in the early stage of immersion. However, an inhibition in corrosion kinetics occurred after longer immersion times due to corrosion product deposition inside the pit.}, number={9}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Witharamage, C. S. and Darwish, A. A. and Christudasjustus, J. and Soltis, J. and Gupta, R. K.}, year={2023}, month={Sep} }
 @article{christudasjustus_larimian_esquivel_gupta_darwish_borkar_gupta_2022, title={Aluminum alloys with high elastic modulus}, volume={320}, ISSN={["1873-4979"]}, DOI={10.1016/j.matlet.2022.132292}, abstractNote={Binary Al-5M alloys, containing 5 at.% alloying element (M: Cr, Si, Nb, Mo, and V), have been produced by high-energy ball milling and subsequent spark plasma sintering. X-ray diffraction analysis indicated the solid solubility of the alloying elements to be several orders of magnitude higher than that predicted by the phase diagram. The elastic modulus and hardness of Al-5M alloys, analyzed using nanoindentation, were significantly higher than the commercial Al alloys. High elastic modulus was attributed to the decrease in lattice parameters as a result of the extended solid solubility of the alloying elements.}, journal={MATERIALS LETTERS}, author={Christudasjustus, J. and Larimian, T. and Esquivel, J. and Gupta, S. and Darwish, A. A. and Borkar, T. and Gupta, R. K.}, year={2022}, month={Aug} }
 @article{ozdemir_witharamage_christudasjustus_darwish_okuyucu_gupta_2022, title={Corrosion behavior of a bulk nanocrystalline Al-Fe alloy}, volume={209}, ISSN={["1879-0496"]}, DOI={10.1016/j.corsci.2022.110727}, abstractNote={Nanocrystalline Al-Fe alloy, with uniform microstructure and high solid solubility of Fe, has been produced by high-energy ball milling. Cyclic potentiodynamic polarization tests revealed high pitting potential. Hardness and corrosion resistance of the Al-Fe alloy were higher than any commercial Al alloy. High hardness and corrosion resistance were attributed to the nanocrystalline structure and formation of solid solution. X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and scanning transmission electron microscopy indicated the incorporation of Fe to the surface film and Fe enrichment at the alloy/surface film interface, which were attributed to the enhanced corrosion performance.}, journal={CORROSION SCIENCE}, author={Ozdemir, F. and Witharamage, C. S. and Christudasjustus, J. and Darwish, A. A. and Okuyucu, H. and Gupta, R. K.}, year={2022}, month={Dec} }
 @article{ozdemir_witharamage_darwish_okuyucu_gupta_2022, title={Corrosion behavior of age hardening aluminum alloys produced by high-energy ball milling}, volume={900}, ISSN={["1873-4669"]}, url={http://dx.doi.org/10.1016/j.jallcom.2021.163488}, DOI={10.1016/j.jallcom.2021.163488}, abstractNote={The influence of high energy-ball milling (HEBM) on corrosion and hardness of age hardening aluminum alloys was investigated. Nanocrystalline age hardening (AA2024, AA6061 and AA7075) alloys were produced by HEBM of pre-alloyed powder and subsequent cold compaction under uniaxial pressure of 3 GPa. Cyclic potentiodynamic polarization and immersion tests were conducted in 0.6 M NaCl solution which revealed significantly increased pitting and protection potentials in the HEBM alloys compared to wrought alloys of same composition. X-ray diffraction analysis and transmission electron microscopy indicated grain refinement below 100 nm in the ball milled alloys which was the major strengthening mechanism in the age hardening HEBM alloys. The superior corrosion resistance and hardness of the age hardening ball milled alloys were attributed to nanocrystalline structure, extended solid solubility and homogenous microstructure- free from coarse intermetallic phases.}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, publisher={Elsevier BV}, author={Ozdemir, Furkan and Witharamage, Chathuranga Sandamal and Darwish, Ahmed Abdelazim and Okuyucu, Hasan and Gupta, Rajeev Kumar}, year={2022}, month={Apr} }
 @article{witharamage_alrizqi_chirstudasjustus_darwish_ansell_nieto_gupta_2022, title={Corrosion-resistant metallic coatings for aluminum alloys by cold spray}, volume={209}, ISSN={0010-938X}, url={http://dx.doi.org/10.1016/j.corsci.2022.110720}, DOI={10.1016/j.corsci.2022.110720}, abstractNote={An Al-V alloy powder produced by high-energy ball milling has been cold sprayed on an AA2024-T3 substrate. The corrosion resistance of cold sprayed alloy, represented by the corrosion current density and pitting potential, was significantly higher than the substrate. Furthermore, a zero-resistance ammeter test revealed that the coating was anodic to the substrate, which would provide cathodic protection in any event of coating breakdown. The wear resistance of the coating was almost four times higher than that of the substrate.}, journal={Corrosion Science}, publisher={Elsevier BV}, author={Witharamage, Chathuranga S. and Alrizqi, Mohammed A. and Chirstudasjustus, Jijo and Darwish, Ahmed A. and Ansell, Troy and Nieto, Andy and Gupta, Rajeev K.}, year={2022}, month={Dec}, pages={110720} }
 @article{vukkum_christudasjustus_darwish_storck_gupta_2022, title={Enhanced corrosion resistance of additively manufactured stainless steel by modification of feedstock}, volume={6}, ISSN={["2397-2106"]}, url={https://doi.org/10.1038/s41529-021-00215-z}, DOI={10.1038/s41529-021-00215-z}, abstractNote={Abstract Additive manufacturing (AM) is an emerging technology to produce engineering components. However, the major challenge in the practical application of AM is the inconsistent properties of additively manufactured components. This research presents a strategy of feedstock modification to improve the corrosion performance of selective laser melted (SLM) 316L stainless steel (SS). Modified feedstock powders were produced by ball-milling of commercial-316LSS powder with 1wt.% chromium nitride (CrN). The SLM coupons produced from modified feedstock powders (SLM-316L/CrN) exhibited significantly improved corrosion performance, as evident from the high pitting and repassivation potentials and absence of metastable pitting. The microstructural characterization revealed fine oxide-inclusions comprising Si, Mn, and S in SLM-316L and only Si and Mn in SLM-316L/CrN. The absence of sulfur-containing oxide-inclusions in SLM-316L/CrN and refined cellular structure, and the change in chemical composition were attributed to corrosion resistance enhancement due to the CrN addition.}, number={1}, journal={NPJ MATERIALS DEGRADATION}, publisher={Springer Science and Business Media LLC}, author={Vukkum, V. B. and Christudasjustus, J. and Darwish, A. A. and Storck, S. M. and Gupta, R. K.}, year={2022}, month={Jan} }
 @article{esteves_christudasjustus_o'brien_witharamage_darwish_walunj_stack_borkar_akans_gupta_2021, title={Effect of V content on corrosion behavior of high-energy ball milled AA5083}, volume={186}, ISSN={["1879-0496"]}, url={https://doi.org/10.1016/j.corsci.2021.109465}, DOI={10.1016/j.corsci.2021.109465}, abstractNote={AA5083 alloys with V additions were produced in the powder form by high-energy ball milling and consolidation by spark plasma sintering and cold compaction. X-ray diffraction and energy dispersive X-ray spectroscopy analysis indicated the formation of supersaturated solid solution and grain refinement below 100 nm. Corrosion behavior was investigated using electrochemical impedance spectroscopy, cyclic potentiodynamic polarization, and immersion corrosion tests followed by surface analysis. The composition of the passive film was obtained via X-ray photoelectron spectroscopy. The corrosion resistance of the AA5083 was significantly improved due to the addition of V and high-energy ball milling.}, journal={CORROSION SCIENCE}, publisher={Elsevier BV}, author={Esteves, L. and Christudasjustus, J. and O'Brien, S. P. and Witharamage, C. S. and Darwish, A. A. and Walunj, G. and Stack, P. and Borkar, T. and Akans, R. E. and Gupta, R. K.}, year={2021}, month={Jul} }
 @article{darwish_hassan_abou mandour_maarouf_2019, title={Mechanical properties of defective double-walled boron nitride nanotubes for radiation shielding applications: A computational study}, volume={156}, DOI={10.1016/j.commatsci.2018.09.04}, journal={COMPUTATIONAL MATERIALS SCIENCE}, author={Darwish, Ahmed A. and Hassan, Mohamed H. and Abou Mandour, Mohsen A. and Maarouf, Ahmed A.}, year={2019}, pages={142–147} }
 @article{darwish_hassan_abou mandour_maarouf_2019, title={Mechanical properties of defective double-walled boron nitride nanotubes for radiation shielding applications: A computational study}, volume={156}, ISSN={["1879-0801"]}, DOI={10.1016/j.commatsci.2018.09.040}, abstractNote={Radiation shielding is of great importance because of the wide-spread use of nuclear radiation in various applications, such as power generation, space industries, nuclear medicine, etc. Current research focuses on developing materials with high shielding efficiency and robust mechanical properties. Boron nitride nanotubes (BNNTs) make good candidate materials for space radiation shielding applications. They are usually mixed with polymer composites to boost their mechanical properties and increase their shielding capability. Shielding can be further enhanced by adding hydrogen to the BNNT lattice, where it binds to atomic sites, or resides in vacancies. These vacancy defects can degrade the mechanical properties of the shielding materials, making them unsuitable for industrial prolonged use. In this work, we study the effect of vacancies on the mechanical properties of double-walled BNNTs (DWBNNTs). Using density functional theory, we calculate Young’s modulus of defective DWBNNTs having up to 4 divacancies, in two configurations, armchair and zigzag. We find that defective armchair DWBNNTs suffer a decrease of 5–25% of their Young’s moduli, while zigzag DWBNNTs show a lesser decrease of 3–15%, relative to the defect-free DWBNNTs. In addition, the divacancies cause a length contraction in the armchair case, and an ellipsoidal deformation for the zigzag one. Our findings are important for predicting of the tolerance of DWBNNTs to space radiation environment.}, journal={COMPUTATIONAL MATERIALS SCIENCE}, author={Darwish, Ahmed A. and Hassan, Mohamed H. and Abou Mandour, Mohsen A. and Maarouf, Ahmed A.}, year={2019}, month={Jan}, pages={142–147} }