目的 通过激光熔覆技术在Ti811钛合金表面制备Ni基复合涂层，以改善其摩擦磨损性能。方法 采用同轴送粉激光熔覆技术在钛合金表面制备Ni45+WC+Y2O3多道搭接激光熔覆层，运用XRD、SEM、EDS分析熔覆层微观组织及相组成，运用Bramfitt二维点阵错配度理论，计算低指数晶面间二维错配度，分析复合相结构。采用显微硬度计测试熔覆层显微硬度值，通过摩擦磨损试验机测试基材和熔覆层的摩擦磨损性能，采用白光非接触式轮廓仪测量基材和熔覆层磨损体积，结合磨损表面形貌，分析熔覆层磨损机制。结果 熔覆层生成相主要包括Ti2Ni、TiB2、TiC、α-Ti以及TiC依附于TiB2的复合生长相。复合相中，TiB2(0001)晶面与TiC(111)晶面受热膨胀影响的二维点阵错配度δ=0.907%，满足晶格界面共格原则，TiB2可有效作为TiC的异质形核基底。熔覆层显微硬度值约为1050~1100HV0.5，摩擦系数约为0.42，磨损体积为4.07×107 μm3，磨损率为3.0×10–4 mm3/(N?m)，磨损机制是以磨粒磨损为主，粘着磨损为辅的混合磨损机制。结论 与基材对比，熔覆层显微硬度值提高约2.5倍，摩擦系数和磨损率分别降低约35%和36%，熔覆层摩擦磨损性能显著提高。

The work aims to fabricate Ni-based composite coating on Ti811 titanium alloy surface by laser cladding technology for the improvement of its friction and wear properties. The Ni45+WC+Y2O3 multi-track cladding layer was prepared on the surface of Ti811 titanium alloy by coaxial powder feeding laser cladding technology. The microstructure and phase composition of the cladding layer were analyzed by XRD, SEM and EDS; and the Bramfitt two-dimensional lattice mismatch theory was applied to calculate the two-dimensional misfit between low-index crystal planes to analyze the structure of composite phase. The microhardness of the cladding layer was examined by microhardness tester and the friction and wear properties of substrates and cladding layer by friction-wear tester. The wear volume of the substrate and cladding layer was measured by white light non-contact profiler; the friction along with the wear mechanism of cladding layer was analyzed based on the wear surface morphology. The results showed that the formation phases of the cladding layer mainly contained Ti2Ni, TiB2, TiC, α-Ti and a composite growth phase in which TiC was dependent on TiB2, and the two-dimensional misfit degree of TiC (111) and TiB2 (0001) crystal planes that was influenced by the thermal expansion was δ=0.907%, meeting the lattice interface coherent principle, indicating that TiB2 can work as the heterogeneous nucleation nucleus for the growth of TiC. The microhardness, friction coefficient, wear volume, wear rate of the cladding layer were about 1050~1100 HV0.5, 0.42, 4.07 ×107 μm3, and 3.0×10–4 mm3/(N?m), respectively. The wear mechanism of the cladding layer was found to be a mixed wear mechanism of abrasive wear as the main and adhesive wear as the auxiliary. Compared with those of the substrate, the microhardness of the cladding layer is improved by 2.5 times; the friction coefficient and wear rate are decreases by 35% and 36%, respectively; the friction and wear properties of the cladding layer are increased significantly.