Ti811合金表面激光熔覆Ti2Ni+TiC+Al2O3+CrxSy复合涂层的组织和性能

以TC4+Ni45+Al₂O₃+MoS₂+Y₂O₃混合粉末为熔覆材料，采用同轴送粉技术在Ti811合金表面进行激光熔覆制备复合涂层，使用SEM、EDS和XRD等手段分析了涂层的微观组织，测试了涂层的显微硬度和摩擦磨损性能。结果表明，在激光熔覆过程中Ti811合金中的Ni和C分别与Ti发生反应，原位生成金属间化合物Ti₂Ni和硬质增强相TiC；MoS₂分解后S与Cr发生硫化反应生成了软质润滑相Cr_xS_y。网状形态的Ti₂Ni、近球状和枝晶形态的TiC以及点状的Al₂O₃，均匀分布在熔覆层中。硬质相强化和软质相润滑的共同作用，使激光熔覆层具有较高的显微硬度和较优良的耐磨性能。激光功率为900 W的熔覆层其平均显微硬度值达1303.5HV_0.5，其耐磨性能最佳。

Microstructure and Properties of Laser Clad Ti2Ni+TiC+Al2O3+CrxSy Composite Coating on Ti811 Alloy

The composite coating of Ti₂Ni+TiC+Al₂O₃+Cr_xS_y was laser cladded on the surface of Ti811 alloy via coaxial powder feeding technology with mixed powders TC4+Ni45+Al₂O₃+MoS₂+Y₂O₃ as cladding material. The microstructure, microhardness, friction and wear properties of the coating were characterized by means of SEM, EDS, XRD, microhardness tester and friction tester. The results show that the Ni and C of Ti811 alloy react with Ti respectively during laser cladding, so that the intermetallic compound Ti₂Ni and hard reinforced phase TiC can form in situ, while the soft lubrication phase Cr_xS_y also formed due to the sulfurization reaction between S and Cr after the decomposition of MoS₂. The Ti₂Ni-phase may present as network-like, TiC as spheroidal and dendritic, while Al₂O₃ as punctiform, which all uniformly distributed in the clad coating. The combined action of strengthening of the hard phase and lubrication of the soft phase makes the laser clad coating with higher microhardness and better wear resistance. When the laser power is 900W the average microhardness of the clad coating reaches 1303.5HV_0.5 with the best wear resistance.