@article{vukkum_sanborn_shepherd_saptarshi_basu_horn_gupta_2024, title={Influence of Spatter on Porosity, Microstructure, and Corrosion of Additively Manufactured Stainless Steel Printed Using Different Island Size}, volume={14}, ISSN={["2073-4352"]}, url={https://doi.org/10.3390/cryst14040328}, DOI={10.3390/cryst14040328}, abstractNote={Specimens of 316 L stainless steel were printed using laser powder bed fusion (LPBF), a popular metal additive manufacturing (AM) technique, with varying island sizes. Not many researchers have considered the impact of spatter while optimizing LPBF printing parameters. In this research, the influence of spatter was considered while also investigating the effect of varied island size on the microstructure, surface roughness, microhardness, and corrosion resistance of LPBF-316 L. No correlation was observed between surface roughness or microhardness and minor variations in island size. However, a correlation was drawn between varied island sizes and porosity in LPBF-316 L. The specimens associated with larger island sizes showed significantly enhanced corrosion resistance due to fewer manufacturing defects and reduced porosity, attributed to the minimal influence of the spatter. Based on analysis, the LPBF parameters were revised, which lead to superior corrosion resistance of LPBF-316 L, attributed to high density and reduced porosity.}, number={4}, journal={CRYSTALS}, author={Vukkum, Venkata Bhuvaneswari and Sanborn, Taylor and Shepherd, John and Saptarshi, Sourabh and Basu, Rakesh and Horn, Timothy and Gupta, Rajeev Kumar}, year={2024}, month={Apr} }
 @article{mugale_choudhari_karki_desai_walunj_vukkum_schwam_gupta_borkar_2024, title={Investigation of Protective Coatings for Reducing High-Temperature Oxidation of Steels}, volume={10}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-024-06912-9}, abstractNote={Abstract Oxidation of steel billets during pre-heating at elevated temperatures is a challenge, particularly in the forging industry. There is a need to address this problem by applying effective oxidation-resistant coatings on forging billets. In this investigation, different types of commercially available high-temperature, oxidation-resistant coatings, termed Coating A, B, C, D, E, F, and G, were applied on AISI 4340 low-alloy steel by spraying and dipping at room temperature. The oxidation protection behavior of each coating was studied over a wide range of temperatures and holding times in atmospheric conditions. The weight and height losses caused by oxidation were measured, and the samples were subsequently characterized using XRD and SEM-EDS. The protection mechanisms and anti-oxidation properties of the coatings are discussed in detail. The sample coated with Coating A showed the best protection at all temperatures compared to other coatings. The weight/height loss of Coating A-coated steel samples was reduced by 80–90% compared to an uncoated/bare sample. Coating A not only limited the outward diffusion of iron cations from the substrate but also prevented the inward diffusion of oxygen anions from the atmosphere, resulting in better oxidation resistance. The findings of the study should apply to other steels with similar compositions.}, journal={JOM}, author={Mugale, Manoj and Choudhari, Amit and Karki, Sanoj and Desai, Jay and Walunj, Ganesh and Vukkum, Venkata B. and Schwam, David and Gupta, Rajeev Kumar and Borkar, Tushar}, year={2024}, month={Oct} }
 @article{christudasjustus_vukkum_gupta_2023, title={Evolution of surface film in AA2024-T3 after a long-term immersion in NaCl solution}, volume={215}, ISSN={["1879-0496"]}, url={http://dx.doi.org/10.1016/j.corsci.2023.111056}, DOI={10.1016/j.corsci.2023.111056}, abstractNote={Surface films of AA2024-T3 after immersion in 0.1 M NaCl for 14 days, 6 months, and 1 year have been investigated using scanning electron microscopy. The corrosion product generated on the surface over the immersion period was comprised of porous outer and compact inner layers. The Cu enrichment at the corrosion product/metal interface and Cu clusters within the surface films have been observed. Exfoliation corrosion was observed, which allows the electrolyte to migrate through exfoliated path and cause rapid corrosion at sub-surface level. Mechanistic aspects of surface film, Cu cluster formation, and corrosion under the surface film have been discussed.}, journal={CORROSION SCIENCE}, publisher={Elsevier BV}, author={Christudasjustus, J. and Vukkum, V. B. and Gupta, R. K.}, year={2023}, month={May} }
 @article{vukkum_christudasjustus_ansell_nieto_gupta_2023, title={Influence of carbon nanotubes on microstructure and corrosion performance of additively manufactured 316L stainless steel}, url={https://doi.org/10.1016/j.corsci.2023.111494}, DOI={10.1016/j.corsci.2023.111494}, abstractNote={Laser powder bed fusion (LPBF) was performed on feedstock-modified 316L stainless steel powder with 1 and 2 vol% carbon nanotubes (CNT). The corrosion resistance was evaluated following cyclic potentiodynamic polarization tests conducted in 0.6 M NaCl at room temperature, 35 and 50 °C, and immersion tests in 6 % FeCl3. The CNT addition has increased the pitting potential and decreased number of pits formed during immersion in FeCl3 solution, which could be attributed to Mn-Si-O nano inclusions refinement and segregation of chromium around the inclusions. The observed corrosion behavior was correlated with the altered microstructure due to CNT addition.}, journal={Corrosion Science}, author={Vukkum, Venkata Bhuvaneswari and Christudasjustus, Jijo and Ansell, Troy Y. and Nieto, Andy and Gupta, Rajeev Kumar}, year={2023}, month={Nov} }
 @article{vukkum_ansell_nieto_gupta_2024, title={Intergranular Corrosion of CNT-Reinforced and Laser Powder Bed Fusion-Printed 316L Stainless Steel}, volume={76}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-023-06165-y}, number={1}, journal={JOM}, author={Vukkum, Venkata Bhuvaneswari and Ansell, Troy Y. and Nieto, Andy and Gupta, Rajeev Kumar}, year={2024}, month={Jan}, pages={232–237} }
 @article{vukkum_ansell_nieto_gupta_2023, title={Intergranular Corrosion of CNT-Reinforced and Laser Powder Bed Fusion-Printed 316L Stainless Steel}, volume={10}, ISSN={["1543-1851"]}, DOI={10.1007/s11837-023-06165}, journal={JOM}, author={Vukkum, Venkata Bhuvaneswari and Ansell, Troy Y. and Nieto, Andy and Gupta, Rajeev Kumar}, year={2023}, month={Oct} }
 @article{vukkum_delvecchio_christudasjustus_storck_gupta_2023, title={Intergranular Corrosion of Feedstock Modified-Additively Manufactured Stainless Steel After Sensitization}, volume={79}, ISSN={["1938-159X"]}, url={https://doi.org/10.5006/4245}, DOI={10.5006/4245}, abstractNote={Laser powder bed fusion (LPBF), a metal additive manufacturing technique, was conducted on feedstock-modified 316L stainless steel (316L) powder produced by ball-milling of commercial 316L and 1 wt% additive (cerium oxide—CeO2, lanthanum (III) nitrate hexahydrate—La(NO3)3·6H2O, and chromium nitride—CrN). The feedstock-modified LPBF-316L specimens were sensitized at 675°C for 24 h, and the influence of additives on intergranular corrosion (IGC) was investigated following ASTM G108-94 and A262-14 standards. The LPBF-316L with La(NO3)3·6H2O showed higher IGC resistance. The microstructure of the LPBF specimen was investigated and correlated to understand the improved IGC resistance of LPBF-316L with La(NO3)3·6H2O additive.}, number={6}, journal={CORROSION}, author={Vukkum, Venkata Bhuvaneswari and Delvecchio, Evan and Christudasjustus, Jijo and Storck, Steven and Gupta, Rajeev Kumar}, year={2023}, month={Jun}, pages={624–636} }
 @article{vukkum_ray_karmakar_das_2023, title={Microstructure-Texture-Mechanical Property Correlation in Laser-Welded Dual-Phase and Interstitial-Free Steel Blanks}, volume={2}, ISSN={["1544-1024"]}, DOI={10.1007/s11665-023-07959-6}, journal={JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE}, author={Vukkum, V. B. and Ray, T. and Karmakar, A. and Das, S.}, year={2023}, month={Feb} }
 @article{christudasjustus_witharamage_vukkum_walunj_borkar_gupta_2023, title={Surface Film Formation on Al-V Alloys with Far-From-Equilibrium Microstructure}, volume={170}, ISSN={["1945-7111"]}, url={https://doi.org/10.1149/1945-7111/acc7ce}, DOI={10.1149/1945-7111/acc7ce}, abstractNote={Nanocrystalline supersaturated Al-V alloys produced by high-energy ball milling have been reported to exhibit enhanced corrosion resistance and mechanical properties compared to commercial Al alloys. Corrosion of passive alloys such as Al-V alloy relies on the characteristics of the surface film, which is studied using scanning/transmission electron microscopy and time-of-flight secondary ion mass spectrometry. The effect of microstructure and composition on the surface film has been investigated after different immersion periods (30 min, 2 h, and 1 day) in 0.1 M NaCl. The surface film was complex and composed of oxidized Al and V. The heterogeneous surface film was observed due to the presence of secondary phases and initiation of localized corrosion. The void formation was observed beneath the surface film that would potentially cause pitting corrosion. The generation of nano-sized voids was dependent on grain orientation. Compared to pure Al, the chloride penetration is suppressed in Al-V alloys. The effect of composition and microstructure on surface film formation and attendant corrosion behavior is discussed herein.
               
                  
                     
                  
               }, number={3}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Christudasjustus, J. and Witharamage, C. S. and Vukkum, V. B. and Walunj, G. and Borkar, T. and Gupta, R. K.}, year={2023}, month={Mar} }
 @article{nieto_vukkum_jalagam_nema_budan_gupta_ansell_2022, title={3D printed carbon nanotube reinforced stainless steel via selective lase melting}, volume={8}, ISSN={["2159-6867"]}, DOI={10.1557/s43579-022-00200-w}, abstractNote={Carbon nanotubes (CNT) are integrated into 316L stainless steel (SS) powder feedstocks and 3D-printed using selective laser melting (SLM). Ball milling is used to disperse CNT clusters homogeneously onto the surface of 316L SS powders with minimal damage to the CNTs. Hardness increased by 35% and wear was reduced by 70% with the addition of 2 vol% CNT, relative to SLM 316L SS. The addition of CNTs increased the water contact angle and retained the desirable corrosion resistance of SLM 316L SS, demonstrating the potential of 3D-printed SS-CNT composites for use in structural marine applications. Graphical abstract}, journal={MRS COMMUNICATIONS}, author={Nieto, Andy and Vukkum, Venkata Bhuvaneswari and Jalagam, Prajna and Nema, Kanishq and Budan, Justin and Gupta, Rajeev Kumar and Ansell, Troy Y.}, year={2022}, month={Aug} }
 @article{vukkum_ozdemir_storck_gupta_2022, title={Corrosion performance of feedstock modified - Additively manufactured stainless steel}, volume={209}, ISSN={["1879-0496"]}, DOI={10.1016/j.corsci.2022.110724}, abstractNote={Feedstock modified powders were produced by ball-milling commercial 316 L stainless steel powder and 1 wt% additive (Cerium oxide–CeO2, lanthanum (III) nitrate hexahydrate–La(NO3)30.6 H2O and chromium nitride–CrN). Laser-powder bed fusion (L-PBF) was performed on modified feedstock using 180, 200, and 220 W laser power. The influence of additives on microstructure and corrosion performance was investigated on the as-printed and ground/polished conditions of L-PBF-316 L-additive. The corrosion performance was dependent on the type of the additives. The microstructure of the alloys was correlated with the observed corrosion behavior.}, journal={CORROSION SCIENCE}, author={Vukkum, V. B. and Ozdemir, Furkan and Storck, Steven and Gupta, R. K.}, year={2022}, month={Dec} }
 @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={http://dx.doi.org/10.1038/s41529-021-00215-z}, DOI={10.1038/s41529-021-00215-z}, abstractNote={AbstractAdditive 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{ozdemir_christudasjustus_vukkum_okuyucu_gupta_2022, title={Need of an Inert Atmosphere for High-Energy Ball Milling of Al Alloys}, volume={9}, ISSN={["1544-1024"]}, url={https://doi.org/10.1007/s11665-022-07309-y}, DOI={10.1007/s11665-022-07309-y}, journal={JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE}, author={Ozdemir, F. and Christudasjustus, J. and Vukkum, V. B. and Okuyucu, H. and Gupta, R. K.}, year={2022}, month={Sep} }
 @misc{vukkum_gupta_2022, title={Review on corrosion performance of laser powder-bed fusion printed 316L stainless steel: Effect of processing parameters, manufacturing defects, post-processing, feedstock, and microstructure}, volume={221}, ISSN={["1873-4197"]}, DOI={10.1016/j.matdes.2022.110874}, abstractNote={The applications of laser-powder bed fusion (LPBF), an emerging additive manufacturing (AM) technique, are rapidly growing in various industries. The superior and consistent mechanical and corrosion properties of LPBF-printed components are essential for engineering applications. The 316L stainless steel (SS) is an essential alloy with widespread applications from household items to nuclear and aerospace industries. Extensive research is conducted to understand and improve the mechanical properties of LPBF printed 316L SS. Studying the corrosion behavior of LPBF printed 316L has attracted only limited attention. Additionally, a discrepancy in the corrosion performance of LPBF printed 316L has been reported due to the complex microstructure and defects introduced during LPBF. Therefore, understanding the influence of processing parameters and feedstock on defects and microstructure becomes critical in understanding the processing-corrosion relationships and producing LPBF printed 316L components with reproducible properties. This review presents the influence of feedstock, processing parameters, and post-processing techniques on manufacturing defects, microstructure, and corrosion performance of LPBF printed 316L. Strategies and hypotheses to improve the corrosion resistance of LPBF printed 316L are also presented.}, journal={MATERIALS & DESIGN}, author={Vukkum, V. B. and Gupta, R. K.}, year={2022}, month={Sep} }