High temperature wear in CoCrFeNiCux high entropy alloys: The role of Cu

A series of CoCrFeNiCux (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) high entropy alloys (HEA) were prepared using arc melting technique and the effect of Cu on microstructure evolution and wear was studied both at room and high temperature. Microstructure reveals two phases, namely, CoCrFeNi and pure Cu. Wear rate at room temperature (RT) as well as at elevated temperatures (ET) decreases with increase in Cu content. However, wear resistance is found to be more at ET than RT. This is attributed to the self-lubricating behaviour of Cu at elevated temperature.