摘要

A Fe-based composite coating reinforced by in situ synthesized TiC particles was fabricated on Cr12MoV steel by using 6KW fiber laser cladding. A serial of experiment has been carried out with different laser power, scanning speed, and powder feed rate, from which TiC could be in situ synthesized only in certain realms laser cladding parameters. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscope and a hardness tester are used to test the microstructure, micro-hardness and component distribution. The coating is mainly composed of alpha;-Fe, TiC and Fe3C. TiC particles were commonly precipitated in three kinds of morphologies, such as quadrangle, cluster, and flower-like shape. The grains were refined, and there were no cracks and few stomas. Defect-free coating with metallurgical joint to the substrate was obtained. TiC distributed more concentratively in the upper layers than the middle and bottom layers. From the surface of cladding layer 0.8 mm the highest micro-hardness was up to HV930, obviously higher than that of the substrate.