Abstract:The cobalt-based composite coating reinforced with in-situ synthesized multiple particles was fabricated on TA15 titanium alloy surface by transverse flow CO2 laser adopting the optimizing laser cladding process parameters to improve wear resistance and hardness in surface. X-ray diffraction (XRD), metallurgical microscope, scanning electron microscope (SEM), hardness tester and wear testing machine were used to analyze the coating. The results show that the microstructures of the coating are mainly composed of γ-Co, α-Ti solid solution and in-situ synthesized TiB2, Cr5Si3, TiC, WB, SiC, Co3Ti and NiC particles. And these multiple granular reinforced phases are dispersively distributed among the fine dendritic structures in the cladding layer. The microhardness of the cladding layer compared with that of the substrate, has been improved a lot, HV reaching about 10000 MPa which is around three times higher than that of the substrate. Compared to titanium alloy, the wear resistance of the cladding layer has been distinctly improved, and the wear rate of the cladding layer is about 1/12 of the titanium alloy. The wear mechanism of the cladding layer is a mixed type of adhesion and abrasion