THE INFLUENCE OF PREHEATING TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF LASER-CLAD Ni-BASED COMPOSITE COATINGS CONTAINING (Ti, V)C

Ni-based composite coatings containing transition metal carbides exhibit high hardness, and the rapid heating and cooling characteristics of laser cladding lead to the formation of cracks in these coatings, significantly limiting their practical industrial applications. In this study, (Ti, V)C/Ni composite coatings were prepared at different preheating temperatures to investigate the effect of preheating on crack formation. The microstructure of the coatings was investigated by XRD, OM, and SEM, and the differences in wear resistance were studied by block-on-ring wear tests. The results show that with increasing preheating temperature, the residual stress in the coatings decreases significantly, the secondary dendrite arm spacing increases, and the number of cracks decreases. No crack defects were observed in the coating preheated at [Formula: see text]C, indicating that substrate preheating can effectively suppress crack formation during the laser cladding process. Compared with the coating prepared without preheating, the hardness and wear resistance of the coating prepared by preheating at [Formula: see text]C were reduced, which was still 5.6% higher than that of the substrate after quenching, and the wear resistance was 1.76 times higher than that of the substrate.