激光熔覆钛基金属陶瓷复合涂层的组织与性能

Microstructure and properties of laser clad titanium-based cermet composite coating

为了提高TC4合金的耐磨减摩性,利用激光熔覆技术在TC4合金表面激光熔覆TC4+h-BN混合粉末制备钛基金属陶瓷复合涂层,利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱分析仪(EDS)等手段对熔覆层宏观形貌和微观组织进行观察,利用显微硬度计对熔覆层、热影响区、基体的硬度进行测试,通过摩擦磨损试验机对熔覆层和基体的摩擦因数进行测量,利用电子精密天平对熔覆层和基体的磨损量进行检测。结果表明:熔覆层主要由杆状相TiB、三元共晶组织(Ti-B-N)和基底α-Ti组成。熔覆层硬度分布在1000~1200 HV0.5之间,熔覆层磨损机理为轻微的磨粒磨损,TC4基体为严重的磨粒磨损。熔覆层摩擦因数较基体下降了0.04,磨损量较基体下降了7 mg,熔覆层的耐磨减摩性能较基体有所提高。

In order to improve the wear-resistance and anti-friction properties of TC4 alloy,a titanium-based composite coating was prepared on the TC4 alloy surface by laser cladding technique with TC4+h-BN mixed powder.The macroscopic morphology and microstructure of the clad layer were studied by using XRD,SEM,EDS,etc.,and the hardness of the clad layer,heat affected zone and matrix was tested by microhardness tester.The friction coefficient and the wear mass loss of the clad layer and matrix were respectively determined by friction and wear tester and electronic precision balance.The results show that the clad layer is mainly composed of rod phase TiB,Ti-B-N ternary eutectic structure and substrateα-Ti.The hardness of the clad layer is between 1000 HV0.5 and 1200 HV0.5.The wear mechanism of the clad layer and the TC4 matrix is slight abrasive wear and severe abrasive wear,respectively.The friction coefficient and the wear mass loss of the clad layer are reduced by 0.04 and by 7 mg from that of the substrate,thus the wear resistance and friction reduction performance of the clad layer are improved compared with the substrate.