In Situ Laser Synthesis of High Entropy Alloy Coating on Ti-6Al-4V Alloy: Characterization of Microstructure and Properties

In order to improve the surface properties of Ti-6Al-4V, high-entropy alloy coatings were prepared by in-situ laser cladding on the surface of Ti-6Al-4V substrate. The microstructure, micro-hardness, corrosion resistance and wear resistance were investigated. The results showed that the high-entropy alloy coating was composed of BCC high-entropy alloy phase, α-Ti phase and (Ni, Co)Ti2 phase. The micro-hardness of the high-entropy alloy coatings is much higher than that of Ti-6Al-4V substrate. The coating also has a better corrosion resistance than Ti-6Al-4V substrate, even superior to 304SS in 3.5wt.% NaCl solution at room temperature. Compared with Ti-6Al-4V substrate, the high-entropy alloy coating has a greater wear resistance with the wear mass loss decreased 28.2% and 23.1%, respectively. Wear patterns of Ti-6Al-4V substrate and high-entropy alloy coatings are the coexistence of adhesive wear and abrasive wear, but the wear degree of high-entropy alloy coatings is lower.