Effects of normal load and velocity on the dry sliding tribological behaviour of CoCrFeNiMo0.2 high entropy alloy

A systematic experimental study has been conducted to evaluate the sliding tribological properties of CoCrFeNiMo0.2 high entropy alloy at room temperature. The results showed strong dependence of its friction and wear behaviours on sliding duration, normal load and velocity. Increase in load led to decrease of both friction coefficient and specific wear rate, while increase in velocity resulted into decrease of friction coefficient but increase of specific wear rate. Detailed wear mechanisms were investigated by examining the worn surface morphology, chemical composition and its cross-sectional microstructures. The dominant wear mechanisms changed gradually from abrasion and plastic deformation to oxidation wear and delamination with increasing the sliding duration and normal load. Moreover, abrasion and adhesion played the main roles at high sliding velocities. (1)Systematic dry sliding wear tests of CoCrFeNiMo0.2 HEA fabricated by SPS and subsequent cold rolling have been conducted.(2)Both friction coefficient and specific specific wear rate of CoCrFeNiMo0.2 HEA are strongly affected by the sliding parameters.(3)Large amount of wear debris and glaze layer form with increasing the number of sliding cycles and normal load, but decrease significantly with increasing sliding velocity.(4)Main wear mechanisms are oxidation and delamination under high loads, while abrasion and adhesion under high sliding velocities.