Microstructures and wear behaviour of (FeCoCrNi)1-x(WC)x high entropy alloy composites

High entropy alloys (HEAs) have high fracture toughness and good strength, and are promising for wear applications. In order to improve the wear resistance, (FeCoCrNi)1-x(WC)x (x = 3-11, at.%) HEA composites were prepared by spark plasma sintering mechanically alloyed powder. Microstructures and the wear resistance of the HEA composites were evaluated. The microstructures of (FeCoCrNi)1-x(WC)x HEA composites consist of four phases: FCC matrix phase, WC-type carbide, M23C6-type and M7C3-type carbides. The hardness of the (FeCoCrNi)1-x(WC)x HEAs composites gradually increases with the increase of WC content from 603 HV to 768 HV at room temperature, much higher than those of other HEAs. The strengthening effect is mainly attributed to the existence of W-rich and Cr-rich carbides. The coefficients of friction (COFs) increase first with the content of WC increasing to 7%, and then drop. However, the wear loss mostly increases with the content of WC. The worn mechanism also changes from adhesive one for low-WC composites to abrasive one for high-WC.