Microstructure and Tribological Properties of Laser Cladding Self-Lubricating Anti-Wear Composite Coatings on TA2 Alloy

Three different self-lubrication anti-wear composite coatings were fabricated on TA2 titanium alloy by laser cladding with different powder mixtures: 40%Ti–19.5%TiC–40.5%WS₂, 40%Ti–25.2%TiC–34.8%WS₂, 40%Ti–29.4%TiC–30.6%WS₂ (w). The microstructure, phase compositions, microhardness and tribological properties of coatings were investigated systematically. The results have demonstrate that the microhardness of the three different coatings were HV_0.5 927.1, HV_0.5 1007.5 and HV_0.5 1052.3, respectively. The microhardness of coatings were improved dramatically compared with the TA2 titanium alloy (HV_0.5 180). The coefficient of friction and the wear rate of those coatings were 0.41 and 30.98×10^–5 mm³/(N·m), 0.30 and 18.92×10^–5 mm³/(N·m), 0.34 and 15.98×10^–5 mm³/(N·m), respectively. The coating fabricated with the powder mixtures of 34.8% and 30.6% WS₂ presented excellent anti-wear and friction reduction properties. The main wear mechanism were mild plastic deformation and adhesive wear.