Influence of Graphene Sheet on Microstructure and Properties of Ni-based Alloy Coatings Prepared by Laser Cladding

摘要

Ni-based alloy cladding layers with different graphene sheet additions were prepared by laser cladding on the 40CrNi2Si2MoV steel substrate. The influence of the graphene sheet on the microstructure and properties of the cladding layers was investigated. The results show that owing to the diffusion-reaction dissolution, the graphene sheet addition does not bring a corresponding change in the phase constitutions of the cladding layers, i. e., the cladding layers are still composed of γ-Ni, Ni3B, and M7C3 phases. But what has changed is that the solidified structure is refined, and the volume fractions of the eutectic and the carbide are increased with the increase of graphene sheet addition. As a result, the hardness and the wear resistance of the cladding layers gradually increase, whereas the friction coefficient firstly decreases and then increases, with the lowest friction coefficient obtained at 0.5?vol.% graphene sheet addition. Compared to the Ni-based alloy cladding layers with micro-size graphite additions, the studied cladding layers exhibit improved hardness and wear resistance, good forming quality, and increased friction coefficient.