Microstructure and wear behaviors of TiB/TiC reinforced Ti₂Ni/α(Ti) matrix coating produced by laser cladding

A Ti₂Ni/α(Ti) matrix composite coating reinforced by TiC and TiB was prepared on a Ti6Al4V substrate by laser cladding. The microstructure of the coating was examined and discussed. The wear behavior of the coating at various sliding speeds was investigated from the perspective of energy dissipation, and the relationship between accumulated dissipated energy (ΣE) and accumulated wear volume (ΣV) was established. Results indicate a good linear relationship between ΣE and ΣV at low sliding speed (0.1 m·s⁻¹); at higher sliding speed (0.2 m·s⁻¹), the relationship between these parameters follows a quadratic function. The results may be explained from the perspective of energy transformation, wherein the friction heat and plastic deformation of the coating surface consume a substantial amount of ΣE at high sliding speed (0.2 m·s⁻¹) and the remainder of the energy is used to produce worn coating debris. The wear mechanism of the coating involves a combination of microcutting and brittle debonding accompanied by oxidization of the worn surface and formation of Al₂O₃ adherents.