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以TiB2粉末和Ni+TiB2粉末混合物分别作为预置层,采用激光原位技术在钛合金表面制备出2类复合涂层.运用XRD,SEM,EPMA与硬度计等实验手段,对合成的复合涂层进行测试分析.结果表明,Ni添加之前,可获得TiB2颗粒与TiB短纤维增强钛基复合涂层,但涂层表面成型质量较差.Ni添加之后,既可改善涂层的表面成型质量,又可生成bcc结构的NiTi合金填充在TiB2颗粒与TiB短纤维周围.Ni的添加还可使TiB2颗粒得以细化,且涂层中出现了b-Ti基.Ni的添加使涂层的显微硬度值降低,但涂层的断裂韧性得以提高.钛基复合涂层主要通过颗粒脱粘与短纤维断裂偏移方式使裂纹发生偏转来提高涂层的断裂韧性.
Two kinds of composite coatings were prepared on the surface of titanium alloy by laser in-situ technique with TiB2 powder and Ni + TiB2 powder mixture as pre-treated layers respectively. The effects of XRD, SEM, EPMA and hardness tester on the composite coating The results showed that TiB2 particles and TiB short fiber reinforced Ti-based composite coatings could be obtained before the addition of Ni, but the quality of the coating surface was poor.The addition of Ni could not only improve the surface forming quality of the coatings, But also generate bcc structure of NiTi alloy filled in the TiB2 particles and TiB short fibers around .Ni addition TiB2 particles can be refined, and the coating appears b-Ti-based .Ni added so that the microstructure The hardness decreases, but the fracture toughness of the coating can be improved.The Ti-based composite coating can improve the fracture toughness of the coating mainly by deflecting the crack by the way of particle debonding and short fiber fracture offsetting.