SiC/Ti6Al4V复合材料界面反应产物的形成序列及扩散路径(英文)

The Formation Sequence of Interfacial Reaction Products and Diffusion Path in SiC /Ti6Al4V Composite

通过 SiC/Ti6Al4V 钛基复合材料的制备及在不同条件下的热处理试验,利用 SEM, EDS 及 XRD 分析技术研究复合材料界面反应产物相的形成及反应元素的扩散路径。结果表明:反应元素如 C,Ti,Si 在界面反应层中出现浓度波动,合金元素 Al 并没有显著扩散进入界面反应产物层,而是在界面反应前沿堆积,其界面反应产物被确认为 Ti3SiC2 ,TiCx, Ti5Si3Cx和Ti3Si;在界面反应初期,存在着 TiC+Ti5Si3Cx 双相区,当形成各界面反应产物单相区时,SiC/Ti6Al4V 复合材料界面反应扩散的完整路径应为: SiC ┃ Ti3SiC2 ┃ Ti5Si3Cx ┃ TiCx ┃ Ti3Si ┃ Ti6Al4V+TiCx;界面反应产物层的生长受扩散控制,遵循抛物线生长规律,其生长激活能 Qk及 k0分别为 290.935 kJ·mol-1,2.49×10-2 m·s-1/2。

SiC continuous fiber-reinforced Ti6Al4V matrix composites were fabricated and then heat-treated in vacuum under different conditions. The formation of interfacial reaction products and the diffusion path were studied by using of SEM, EDS and XRD methods. The results showed that the content fluctuation of reactive elements such as C, Ti and Si appeared in interfacial reaction layers. Alloying element Al in matrix did not diffuse into interfacial reaction zone remarkably, but piled up in front of the matrix-reaction layer interface, and the interfacial reaction products were identified as Ti3SiC2, TiCx, TisSi3Cx and Ti3Si; At the beginning of interfacial reaction, there was a TiCx＋ Ti5Si3Cx duplex-phase zone. As soon as every single-phase zone formed, the whole diffusion path was to be SiC ｜ Ti3SiC2 ｜ Ti5Si3Cx ｜ TiCx ｜ Ti3Si｜ Ti6Al4V＋TiCx; The interfacial reaction layer growth is controlled by diffusion and follows a role of parabolic rate, and the activation energy Q^k and k0 of SiC /Ti6Al4V are 290.935 kJ·mol^-1 and 2.49× 10^-2 m·s^-1/2, respectively.