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

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, gamma-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 mu m) 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. (C) 1998 Elsevier Science S.A.