Microstructure and Properties of Laser Cladding Graphene Reinforced CoCrFeNiTi High-Entropy Alloy

Abstract

The graphene (Gr) reinforced CoCrFeNiTi high-entropy alloys (HEAs) were prepared, using laser cladding technology based on CO₂ gas laser. The effect of Gr on microstructure, mechanical properties, and corrosion resistance of the HEAs is studied. The experimental results indicate that the main microstructure of Gr/CoCrFeNiTi HEAs is equiaxed grains, with precipitated phases filled between the grains. Graphene plays a role in refining grains. The Gr/CoCrFeNiTi HEAs composite coating consists of the face centered cubic (FCC), body centered cubic (BCC), and M₂₃C₆ in-situ formed carbides. Graphene ptroduces the effect of promoting the formation of BCC and M₂₃C₆ carbides. The coatings hardness tends to increase with the increase of Gr addition, and the hardness is closely related to solid solution strengthening, fine grain strengthening, and dispersion strengthening. As Gr increases, the both wear resistance and corrosion resistance increase first and then decrease. The hardness, Gr, and the content of hard and brittle carbides in the coating have impact on the wear resistance.