Microstructure and Mechanism of Ti2AlNb/TiC+Ti3SiC2 Gradient Materials by In-situ Reaction Laser Cladding

Neng LI
2018 Journal of Mechanical Engineering  
中国航发北京航空材料研究院 3D 打印研究与工程技术中心 北京 100095) 摘要: 设计从基体到 Ti 连接层、 Ti+SiC 混合过渡层、 陶瓷复合层的结构, 通过激光熔覆原位反应成功制备 Ti 2 AlNb/TiC+Ti 3 SiC 2 体系梯度材料。通过扫描电子显微镜、能谱分析和 X 射线衍射仪分析了梯度复合层的微观组织。结果表明,层与层之间结合 良好,实现了成分与显微结构的梯度过渡。梯度复合层共有 6 层,总厚度约 1.5 mm,在 Ti+SiC 的混合过渡层中,Ti 与 SiC 反应生成 TiC 和 Ti 5 Si 3 , 并保留了残余的富 Ti 相, 在 Ti+Si+C 的陶瓷复合层中, Ti、 Si、 C 元素反应生成 Ti 5 Si 3 、 TiC 和 Ti 3 SiC 2 。 梯度材料从基体、Ti 连接层、Ti+SiC 混合过渡层再到陶瓷复合层,显微硬度逐渐升高,最高硬度达到 1 341 HV,最外层由 Abstract:The Ti connecting layer-Ti+SiC transition layer-ceramic composite
more » ... mic composite layers structure is designed and the Ti 2 AlNb/TiC+ Ti 3 SiC 2 system gradient material is successfully fabricated by in-situ reaction laser cladding. The microstructures of different layers are analyzed by scanning electron microscope(SEM), energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). The results show that the interlayer bonding is fine and the gradient transition in the composition and the microstructure is realized. The gradient material consists of six composite layers and the total thickness is 1.5 mm. In the Ti+SiC transition layers, Ti and SiC react to produce TiC and Ti 5 Si 3 , and some Ti-rich phases are retained in the layers. In the ceramic composite layers, Ti, Si and C react to form Ti 5 Si 3 , TiC and Ti 3 SiC 2 . The microhardness gradually increases from the matrix, to the Ti connecting layer, the Ti+SiC transition layer and to the ceramic composite layer. The maximum value is 1 341 HV. The ternary Ti 3 SiC 2 in the outermost layer exhibits the evidently lower microhardness than TiC and Ti 5 Si 3 , which leads to a slight decrease in the microhardness of the composite layer. The fabricated gradient materials should exhibit superior heat-resistance due to the presence of refractory TiC, Ti 5 Si 3 and Ti 3 SiC 2 .
doi:10.3901/jme.2018.08.144 fatcat:3khtzgjcbnbmdgm5fpxyac22qa