TA2合金激光熔覆钛基自润滑耐磨复合涂层的高温摩擦学性能

High Temperature Tribological Properties of Laser Cladding Titanium Matrix Self-Lubricating Wear Resistant Composite Coating on TA2 Alloy

为提升TA2合金的摩擦学性能,选用Ti-TiC-WS_2复合粉末在TA2合金表面激光熔覆钛基高温自润滑耐磨复合涂层.系统地分析了涂层的物相、显微组织结构和显微硬度;分别在室温(20℃)、250℃和500℃下测试了基体和涂层的摩擦学性能,并分析了其磨损机理.结果表明:涂层的显微硬度(约HV_(0.5)1 005.4)是基体(HV_(0.5)190)的5倍;由于增强相TiC/(Ti,W)C_(1–x)和自润滑相Ti_2SC/TiS的综合效应,相比基体,复合涂层在所有试验温度下均具有较小的摩擦系数和磨损率;随着温度的升高,涂层的摩擦系数先变小后升高,在250℃下具有最低的摩擦系数(0.257);涂层的磨损率随温度的升高一直降低,在500℃下磨损率最低[0.487×10^(–5) mm^3/(Nm)].

Titanium matrix high-temperature self-lubricating anti-wear composite coating was fabricated by laser cladding with Ti-TiC-WS2 powders to improve its tribological properties. The phase compositions, microstructure and microhardness were investigated systematically. Tribological properties of the composite coating and TA2 alloy were investigated at room temperature（20 ℃）, 250 ℃ and 500 ℃, respectively, and the wear mechanisms are discussed.Results indicate that the microhardness of the coating is HV0.5 1 005.4, which is 5 times higher than that of the substrate（HV0.5 190）. Due to the combined effects of hard TiC/（Ti,W）C1-x carbides and self-lubricating Ti2SC/TiS sulfides,the composite coating had lower friction coefficient and wear rate than that of the substrate at all test temperatures. The friction coefficient of the coating decreased firstly and then increased with the increase of temperature. The lowest friction coefficient was 0.257 at 250 ℃. Wear rate of the coating decreased with the increase of temperature,and the lowest wear rate was 0.487×10^-5 mm^3/（Nm）.