Faculty Publications
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Item Plasma nitriding of AISI 2205 steel: Effects of surface mechanical attrition treatment and chemical etching(Maney Publishing michael.wagreich@univie.ac.at, 2016) Gatey, A.M.; Hosmani, S.S.; Arya, S.B.; Figueroa, C.A.; Singh, R.P.In the present study, surface mechanical attrition treatment (SMAT) and plasma nitriding were conducted on AISI 2205 steel. SMAT was effective in enhancing the surface hardness of the steel by about 80%. The influence of SMAT on the corrosion behaviour of the steel was studied in a 3.5 wt-% NaCl solution. Due to the stable and thicker passive layer, improved corrosion resistance was observed for the SMATed steel. However, nitrogen diffusion during plasma nitriding was impeded by the improved passivation, especially for the lower duration (30 min) of chemical etching/cleaning (i.e. sputter cleaning in hydrogen plasma) of the specimen's surface. Furthermore, high chemical etching duration (120 min) resulted in improved surface hardness and nitriding kinetics. © 2016 Institute of Materials, Minerals and Mining.Item Role of surface mechanical attrition treatment and chemical etching on plasma nitriding behavior of AISI 304L steel(Elsevier B.V., 2016) Gatey, A.M.; Hosmani, S.S.; Figueroa, C.A.; Arya, S.B.; Singh, R.P.In the present study, the effect of surface mechanical attrition treatment (SMAT) on corrosion resistance and plasma nitriding behavior of AISI 304L stainless steel (SS) was investigated. Mechanical twins and deformation induced martensite phase were observed in the SMAT affected region. SMAT improved the corrosion resistance and nitriding kinetics of AISI 304L SS. Effective nitriding time and hence, the thickness of the nitrided layer were increased with increase in the duration of chemical etching and a decrease in the stability of passive layer on the SMATed specimens. Surface hardness of the nitrided specimens was dependent on the formation of expanded austenite (?N) and its decomposition (especially, at higher effective nitriding time). © 2016 Elsevier B.V.Item Development and characteristics of accumulative roll bonded Mg-Zn/Ce/Al hybrid composite(Elsevier Ltd, 2017) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.; Arya, S.B.; Sahu, S.Accumulative roll bonding (ARB) process have been used develop Mg-2%Zn/Ce/Al hybrid composite and microstructure, mechanical and corrosion properties were investigated. The electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) revealed that the grains are significantly reduced and reaches up to 1 ?m in Mg-2%Zn layer and 1.8 ?m in Al layer having high angle misorientation of grain boundaries after subjected to 5-passes of the ARB process. The Al17Mg12, AlMg4Zn11 and Al11Ce3 intermetallic phases were observed through the XRD analysis. Mechanical properties of the hybrid composite improved with increase in the number of ARB passes which is attributed to work hardening, grain refinement and uniform distribution of Ce particles. Presence of Ce in the hybrid composite restricts the phenomenon of dynamic recrystallization and prevents the grain growth during ARB process. The corrosion rate of Mg-Zn/Ce/Al hybrid composite (0.72 mm/y) improved about 3.3 times as compared to that of Mg-2%Zn alloy (2.37 mm/y). © 2017 Elsevier B.V.Item Microstructure Evolution and Mechanical and Corrosion Behavior of Accumulative Roll Bonded Mg-2%Zn/Al-7075 Multilayered Composite(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.; Arya, S.B.; Sahu, S.Multilayered composite of Mg-2%Zn/Al-7075 was developed by accumulative roll bonding (ARB) of wrought Mg-2%Zn and aluminum 7075 alloy. The Mg-2%Zn/Al-7075 multilayered composite exhibited density of 2295 kg/m3 and an average grain size of 1 and 1.3 ?m in Mg-2%Zn and Al-7075 layers, respectively. A thorough microstructural characterization was performed on the composites by scanning electron microscope, electron backscatter diffraction (EBSD), transmission electron microscope and phase analysis by x-ray diffraction. In addition, mechanical properties were evaluated by microhardness and tensile tests. Corrosion behavior of the multilayered composite was examined using electrochemical polarization test. EBSD analysis showed the presence of ultrafine grains with high-angle grain boundaries. The composite exhibited a significant improvement in ultimate tensile strength (~1.82 times) and elongation (~1.5 times) as compared with Mg-2%Zn alloy, after four-pass ARB process. © 2017, ASM International.Item Tribo-corrosion study of nickel-free, high nitrogen and high manganese austenitic stainless steel(Elsevier Ltd, 2018) Vats, V.; Baskaran, T.; Arya, S.B.The electrochemical corrosion and tribo-corrosion behaviors of nickel-free high nitrogen (HN SS) and high manganese containing austenitic stainless steel were studied in simulated body fluids such as Ringer's and artificial saliva solutions (ASS) using tribo-meter attached with the potentiostat. Type 316L SS used as reference alloy for comparison. Open circuit potential (OCP) and potentiodynamic polarization techniques were used to examine the passivation and corrosion behavior of both the stainless steels under the applied loads of 5 and 10 N at room temperature and also compared with the static condition of corrosion. Pitting resistance of HN SS was found to be significantly higher over type 316L SS. © 2017 Elsevier LtdItem Electrochemical corrosion behavior of Ti-10V-2Fe-3Al in different corrosive media(Wiley-VCH Verlag info@wiley-vch.de, 2018) Arya, S.B.; Bhattacharjee, A.; Roy, M.The electrochemical corrosion behavior of Ti-10V-2Fe-3Al in different corrosive media namely, artificial sea water solution, Hank's solution, 0.5 M sulfuric acid, and 0.5 M hydrochloric acid solution has been investigated. Corrosion rates are evaluated using open circuit potential, current time transient, Tafel extrapolation potentiodynamic polarization curves, and electrochemical impedance spectroscopy. The results show that this alloy has lower corrosion rate in alkaline solution due to formation of thick, compact, and stable passive film. In acid solution corrosion rate is higher as the passive film is less compact, porous, and unstable. In general, the material is more active in C1? ion containing solution. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimItem Electrochemical and Exfoliation Corrosion Behavior of Reversion-Treated High-Strength Aluminum Alloy(Springer, 2020) Nandana, M.S.; Bhat, K.U.; Manjunatha, C.M.; Arya, S.B.The present study aims to understand the microstructural modification affecting the electrochemical and exfoliation corrosion (EXCO) characteristics of aluminum alloy 7010. The alloy was aged for two different tempers, namely peak aging (T6) and retrogression and re-aging (RRA). The standard electrochemical polarization tests and EXCO tests were performed on the treated alloys. The microstructure of the alloy observed under a scanning transmission electron microscope revealed the presence of continuous grain boundary precipitates in T6 alloy. These precipitates were formed discontinuously after RRA treatment. The RRA alloy microstructure resulted in a shift toward positive potential. The exfoliation corrosion depth was reduced to 60–70 ?m after RRA treatment, which was measured to be about 250 ?m in T6 condition. The resistance toward the exfoliation corrosion was found to be influenced by the enriched Cu content of precipitates on grain boundary after reversion treatment. The results confirm that the RRA-tempered alloy improves both electrochemical corrosion and EXCO resistance. © 2020, The Indian Institute of Metals - IIM.