Enhanced surface properties of a graphene oxide reinforced high-entropy alloy composite prepared by spark plasma sintering

Graphene oxide (GO) has been proved to be a potential reinforcement. In this paper, 0.3 wt%, 0.6 wt%, and 1.0 wt% GO reinforced Fe22Co24Cr20Ni23Al11 high-entropy alloy (HEA) composites and pure HEA were synthesized by spark plasma sintering (SPS) to improve the surface properties of HEA. The surface properties including hardness and wear resistance of various samples were comparatively investigated. The experimental results indicated that the surface hardness and wear resistance were enhanced as the content of GO increased (when the GO content was less than 0.6 wt%), which were attributed to the grain refinement strengthening and lubrication effect of GO. However, as the content of GO incrementally increased to 1.0 wt%, the hardness exhibited a descending trend and the coefficient of friction (COF) increased, resulting from the agglomeration of GO. Accordingly, the residual indentation and wear track of HEA/0.6 wt% GO exhibited a minimum depth, which further confirmed the results of the nanoindentation and wear tests.