The effect of different Ag addition on microstructure, mechanical properties and tribological behavior of CoCrFeNiMn-Cr₃C₂ composite

Abstract

CoCrFeNiMn high entropy alloy (HEA) matrix composites with Cr3C2 reinforcement (10 wt%) and different mass friction of Ag lubricant (10, 15 and 20 wt%) were produced by spark plasma sintering. The composites consist of HEA’s FCC phase, Cr7C3 phase and Ag phase, and the microstructures of composites are dense and uniform. The ultimate plasticity strain and fracture toughness improve with the addition of Ag increasing at room temperature. The composites exhibit excellent self-lubricating and wear resistance below 400 °C, and the composite with 20 wt% Ag content has the lower friction coefficient and wear rate. The Ag addition exhibits positive role in improving the wear behavior at medium-low temperatures. The main wear mechanisms of the composites are micro-cutting and abrasive wear at low temperatures. At high temperatures, the oxide tribo-layer generates on the wear surface and deeply torn. Oxide wear and surface deformation are the main wear mechanisms.