▎ 摘　　要

FeCoCrNiAl high entropy alloy (HEA) matrix composite containing graphite nanoplates has been produced by spark plasma sintering (SPS). The tribological properties of this composite were tribo-tested under various loads and velocities. The results suggested that compared to the HEA, the graphite nanoplates can reduce the coefficient of friction significantly from 0.5 to 0.8 to 0.27-0.16. Under low load and velocity conditions, the reduction of friction reached 80%, and a negligible wear was obtained. Surface and interface analysis indicated that the excellent tribological performance was attributed to the in-situ formed graphene that smeared on the rubbing interface and the tribo-induced oxide layer which contained nanoscale-wear debris and graphene. The oxide scale formation and the evolution of graphene from graphite nanoplate were assessed in detail, the graphene formation process is similar to a ball milling process, and the nanoscale-wear debris formed a ball configuration that exfoliates graphite nanoplates. This work proposed a graphene formation process through the sliding induced milling, especially for the materials containing fine crystals, which contributes to the lubrication.