Abstract: TiCp reinforced Ni-based alloy composite coatings are clad to 45 steel using laser cladding technique. The microstructure and wear properties of clad coatings are investigated by means of SEM TEM and wear test. The results show that partial dissolution and regrowth of TiC particles occur in the coating. Deformation twin and dislocation are observed at the interface of TiC particle and matrix due to the solidifying stress.The interdiffusion zone is formed between the coating and substrate. The carbide of (Fe,Cr)23C6 and microcrystal of α,γ are discovered in the interdiffusion zone. The amorphous phase of Ni-Si-B-RE is formed in the laser coatings. The addition of rare earth La2O3 can not significantly increase the microhardness of coatings however the friction coefficient of the clad coating can be obviously reduced and the wear resistance of the clad coatings can be enhanced by rare earth. The coating possesses optimal wear resistance when the mass fraction of TiC is 50 %.

Key words: Laser cladding Microstructure, TiCp/Ni-based alloy coating