Microstructural evolution and wear behavior of carbon added CoCrFeMnNi multi-component alloy fabricated by mechanical alloying and spark plasma sintering

In this study, the effect of adding different forms of carbon such as graphite flakes (GF), graphene nanoplatelets (GNP) and carbon nanotubes (CNT) on the microstructure evolution and wear behavior of CoCrFeMnNi multi-component alloy fabricated by mechanical alloying and spark plasma sintering were investigated. Carbon addition of 2 wt% decreased the particle size and the amount of WC contamination due to milling. Post sintering, the phases observed in all the compacts were Ni-rich FCC, Cr-rich M7C3, Cr3C2 and MnO. Carbon addition resulted in coarser microstructure and higher amount of secondary phases like M7C3, MnO, and Cr3C2 resulting in higher hardness. Ball-on-disk wear tests at room temperature showed that the GNP added alloy showed the highest specific wear rate (3.26 mm3/Nm) in spite of highest hardness. The predominant wear mechanism observed for all the alloys were oxidative wear and abrasive wear which were more prominent for the FCC phase. The CNT and GF added CoCrFeMnNi alloy exhibited the least specific wear rates of 0.85 and 0.96 mm3/Nm, respectively compared to 2.77 mm3/Nm for the base alloy. The wear behavior was explained based on microstructure and composition of the phases. (c) 2021 Published by Elsevier B.V.