Microstructure and wear properties of laser clad Ti_2Ni_3Si/Ni_3Ti multiphase intermetallic coatings

摘要

Wear resistant Ti_2Ni_3Si/Ni_3Ti multiphase inter-metallic coatings with a microstructure consisting of Ti_2Ni_3Si primary dendrites and interdendritic Ti_2Ni_3Si/Ni_3Ti eutectic were fabricated on a substrate of 0.2% C plain carbon steel by a laser cladding process with Ti-Ni-Si alloy powders. The Ti_2Ni_3Si/Ni_3Ti coatings have excellent wear resistance and a low coefficient of friction under metallic dry sliding wear test conditions with hardened 0.45% C carbon steel as the silide-mating counterpart. The excellent tribological properties of the coating are attributed to the high hardness, strong covalent-dominant atomic bonds of the ternary metal silicide Ti_2Ni_3Si and to the high yield strength and strong yield anomaly of the intermetallic compound Ni_3Ti.