Fabrication and Properties of Metal-Coated SiTiCO Fiber-Reinforced Ti Matrix Composite

研究了在实际制备过程中金属涂层对单向SiTiCO纤维增强纯钛基复合材料拉伸强度的影响。采用真空热处理工艺将Au涂层SiTiCO纤维引入工业纯钛基体中。Au涂层厚度为0.5~1.0 μ m，采用连续电沉积工艺在薄（0.1 μ m）碳涂层SiTiCO纤维表面进行涂覆。研究了涂层纤维制备后与钛基体之间的界面反应（扩散）行为，并测定了纤维的拉伸强度，发现Au涂层通过形成金属间化合物Au xTi y有效地阻止了SiTiCO纤维与钛基体之间的反应。该Au_xTi_y层作为Ti和SiTiCO纤维之间的扩散阻挡层。提取的纤维的拉伸强度仅比接收的纤维的拉伸强度低10%。界面力学性能受薄碳涂层和SiTiCO纤维表面控制。热暴露对界面性质的影响小到可以忽略不计。形成的Au_xTi_y也提高了复合材料的杨氏模量。研究清楚地表明了Au涂层的SiTiCO纤维增强钛基复合材料的一些优点。

The effect of the metal coatings on the tensile strength of the unidirectional SiTiCO fiber-reinforced commercially pure Ti matrix composites in an actual fabrication process was examined. Au coated SiTiCO fiber was incorporated into commercially pure Ti matrix by vacuum hot processing route. The thickness of Au coating was from 0.5 to 1.0 μm and coating was done on the surface of thin (0.1 μm) carbon-coated SiTiCO fiber by continuous electro-deposition process. The interface reaction (diffusion) behavior between coated fiber and Ti matrix after fabrication was examined and the tensile strength of the extracted fiber from Ti matrix was obtained.It was found that Au coating effectively prevents reaction between SiTiCO fiber and Ti matrix by formation of intermetallic compound Au_xTi_y. This Au_xTi_y layer acts as a diffusion barrier between Ti and SiTiCO fiber. The tensile strength of the extracted fiber was only 10% lower than that of as received one. The interfacial mechanical properties were controlled by thin carbon coating layer and SiTiCO fiber surface. Effects of the thermal exposure on the interface properties was negligibly small. The formed Au_xTi_y also improves Young's modulus of the composite. The studies clearly demonstrated some advantages of the Au coating for SiTiCO fiber-reinforced Ti matrix composites.