Gradient microstructure in laser clad TiC-reinforced Ni-alloy composite coating

Abstract

A gradient TiC–(Ni alloy) composite coating was produced by one step laser cladding with pre-placed mixture powder on a 1045 steel substrate. The clad layers consisted of TiC particles, γ-Ni primary dendrites and interdendritic eutectics. From the bottom to the top of the clad layer produced at 2000 W laser power and 6 mm s−1 scanning speed, TiC particles exhibited a continuous increase both in size (from 0.8 to 4.8 µm) and in volume fraction (from 1.72 to 32.8%). Their morphology changes from small globe to coarse flower-like cluster. Laser processing parameters have a considerable influence on the gradient distribution of TiC particles in the clad layers.