Ti811合金表面激光熔覆Ti_(2)Ni+TiC+Al_(2)O_(3)+Cr_(x)S_(y)复合涂层的组织和性能

Microstructure and Properties of Laser Clad Ti_(2)Ni+TiC+Al_(2)O_(3)+Cr_(x)S_(y) Composite Coating on Ti811 Alloy

以TC4+Ni45+Al_(2)O_(3)+MoS_(2)+Y_(2)O_(3)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;MoS_(2)分解后S与Cr发生硫化反应生成了软质润滑相Cr_(x)S_(y)。网状形态的Ti_(2) Ni、近球状和枝晶形态的TiC以及点状的Al_(2)O_(3),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。

The composite coating of Ti2Ni+TiC+Al_(2)O_(3)+Cr_(x)S_(y)was laser cladded on the surface of Ti811 alloy via coaxial powder feeding technology with mixed powders TC4+Ni45+Al_(2)O_(3)+MoS_(2)+Y 2 O3as 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 Ti C can form in situ,while the soft lubrication phase Cr_(x)S_(y)also formed due to the sulfurization reaction between S and Cr after the decomposition of MoS_(2).The Ti_(2) Ni-phase may present as network-like,TiC as spheroidal and dendritic,while Al_(2)O_(3) as punctiform,which all uniformly distributed in the clad coating.The combined action of strengthening of the hard phase and lu-brication of the soft phase makes the laser clad coating with higher microhardness and better wear resis-tance.When the laser power is 900W the average microhardness of the clad coating reaches 1303.5HV_(0.5) with the best wear resistance.