Faculty Publications
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Item Development and properties evaluation of Mg-6% Zn/Al multilayered composites processed by accumulative roll bonding(Cambridge University Press, 2017) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.; Arya, S.B.; Sahu, S.Accumulative roll bonding (ARB) process was used to develop Mg-6% Zn/Al and Mg-6% Zn/anodized-Al multilayered composites. Microstructural characterization was done using scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattered diffraction, and transmission electron microscopy. An average grain size measured in the roll-bonded layers of Al, anodized Al, and Mg-2% Zn was found to be 1.8 ?m, 1.6 ?m, and 0.6 ?m, respectively. Phases Al17Mg12, AlMg4Zn11, and Al2O3 after 5-pass of ARB were confirmed by X-ray diffraction analysis. The Mg-6% Zn/Al and Mg-6% Zn/anodized Al composites exhibited tensile strengths ?252 MPa and ?256 MPa, respectively, after a 5-pass ARB process. Hardness of the individual layers of composite increased linearly with an increase in the number of ARB passes. Fractographs of the multilayered composite illustrated the ductile failure in Al and anodized Al layers and transgranular brittle fracture in Mg-6% Zn layers. © Materials Research Society 2017.Item Studies on high-temperature erosion behaviour of HVOF sprayed NiCr based composite coatings(Elsevier B.V., 2025) Medabalimi, S.; Hebbale, A.M.; Gudala, S.; Ramesh, M.R.; Gujar, R.; Aravindan, N.; Petr?, J.Solid particle erosion at high temperature is a major problem in many industries and advanced protective coatings are needed to extend the service life of components subjected to harsh environment. The main objective of this study is to investigate the erosion behavior of HVOF sprayed (NiCr) + 5 % Si and (NiCr)+ 2% C based composite coatings at different impact angles and temperature, with specific emphasis on the effect of coating composition. The coatings exhibited excellent erosive wear resistance at elevated temperatures due to the formation of stable oxide layers (CrO, NiCr?O?, SiO?) and the incorporation of silicide phases (Ni?Si) to the NiCrSi coatings. However, NiCrC coatings containing hard carbide phases (such as NiC) showed higher erosion resistance at higher temperatures and normal impact angles (90°) because of their robust microstructure and thermal stability. The analysis of microhardness indicated that NiCrSi coatings provided higher hardness attributable to silicides and were therefore better suited to moderate erosive environments, whereas NiCrC coatings, with slightly lower hardness, exhibited excellent resilience under severe erosive environments. SEM, EDAX and XRD analyses showed that preferential erosion mechanisms were cutting and plowing at oblique angles (30°) and brittle fracture at normal angles (90°). Notably, at 800 °C, NiCrC coatings outperformed the NiCrSi coatings via consistently superior thermal and erosion resistance. These findings indicate that HVOF sprayed NiCrC coatings are suitable for high temperature erosion protection, and NiCrSi coatings are specifically developed for high erosive wear resistance at low impact angles. © 2025 The Author(s)