基于激光熔覆TiC/TiB2的钛合金表面组织及性能研究

在钛合金表面激光熔覆制备TiC/TiB₂复合涂层,分别采用SEM、显微硬度计和摩擦磨损设备分析了TiB₂+15%TiC复合涂层的微观组织和硬度、摩擦磨损性能。实验结果表明:涂层上部组织主要由粗大的TiB₂树枝晶和少量白色颗粒状的TiC/TiB共晶组织组成,涂层中部组织主要由棒状型、细针状型的TiB₂相和小块状的TiC相组成,涂层下部则由树枝型、块状TiB₂相、较大的片状TiC相和少量的小层片状金属间化合物TiAl组成。由测试结果可知,涂层硬度(960HV_0.2)约为基体的(350HV_0.2)的2.7倍。涂层的耐磨性能显著提高,涂层出现较少的剥落、细小磨痕和颗粒碎屑,基体表面主要是犁沟式的磨损。涂层的磨损量为1.132 mg是基体(5.342 mg)的20%。

Study on surface microstructure and properties of titanium alloy based on TiC/TiB2 laser cladding

The TiC/TiB₂ composite coating was prepared by laser cladding on titanium alloy surface.The microstructure,microhardness and wear resistance of TiB₂+15%TiC composite coating were analysed by SEM,microhardness tester and friction and wear equipment respectively.The results show that the upper part of the coating is mainly composed of coarse TiB₂ dendrites and a small amount of white granular TiC/TiB eutectic microstructure,while the middle part of the coating is mainly composed of rod-like,fine needlelike TiB₂ phase and small block Ti C phase.The lower part of the coating is composed of dendritic phase,massive TiB₂ phase,large flake TiC phase and a small amount of minor flake TiAl intermetallic compound.The hardness of the coating(960 HV0.2) is about2.7 times of that of the substrate(350 HV0.2).The wear resistance of the coating is improved significantly,and the coating appears less peeling,slight wear marks and particle debris,and the surface of the substrate is mainly furrow wear.The wear of the coating is 1.132 mg,20% of that of the substrate(5.342 mg).