SiC纤维增强Ti55复合材料的界面研究

Studies on Interface of SiCf/Ti55 Composite

摘要:

利用纤维涂层法（FMC）、结合热压工艺制备了SiC纤维增强Ti55基复合材料（SiCf/Ti55）。主要研究复合材料在经不同条件真空热暴露处理后，其反应产物相形成的反应序列以及界面反应动力学。结果表明，仅C、Si和Ti等元素参与了界面反应。在1000 °C热暴露时，SiCf/Ti55复合材料界面反应产物序列为SiC | Ti3SiC2 | Ti5Si3+TiC | TiC | Ti55。但是，在低温热暴露的复合材料中不存在Ti3SiC2相。SiCf/Ti55复合材料界面反应产物的生长受扩散控制且遵循抛物线生长规律，其生长激活能Qk及指数系数k0分别为198.16 kJ·mol-1，1.79′10-3 m·s-1/2。相比SiCf/Ti复合材料和SiCf/Ti2AlNb复合材料，SiCf/Ti55复合材料拥有一个高稳定性的界面。然而，相比SiCf/Ti600复合材料和SCS-6 SiCf/ super а2复合材料，SiCf/Ti55复合材料中的纤维与基体更容易发生反应，且界面层更容易生长。

Abstract:

The SiC fiber reinforced Ti55 composite (SiCf/Ti55) was fabricated by Fiber Coating Method (FCM) and Hot Isostatic Pressing (HIP). After the composites were thermally exposed in vacuum under different conditions, the study on the order of interfacial reaction products and the kinetics of interfacial reaction was performed. The results show that only C, Ti and Si elements take part in the interfacial reaction. The order of interfacial reaction products of SiCf/Ti55 composite exposed at 1000 °C can be identified as SiC | Ti3SiC2 | Ti5Si3+TiC | TiC | Ti55. However, the Ti3SiC2 does not exist in the composites exposed at low temperature. The interfacial reaction layer growth is controlled by diffusion and follows a role of parabolic rate, and the activation energy Qk and the pre-exponential factor k0 of SiCf/Ti55 composite are 198.16 kJ·mol-1 and 1.79′10-3 m·s-1/2, respectively. Compared with the SiCf/Ti composite and SiCf/Ti2AlNb composite, there is an interface with higher stability in SiCf/Ti55 composite. However, the interfacial reaction between SiC fiber and matrix takes place easier in SiCf/Ti55 composite than in the SiCf/Ti600 composite and SCS-6 SiCf/super а2 composite.