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

在实际制备过程中，考察了金属涂层对单向硅钛纤维增强工业纯钛基复合材料抗拉强度的影响。采用真空热加工的方法，将金包覆SiTiCO纤维掺入工业纯钛基体中。采用连续电沉积的方法，在0.1 μm薄碳包覆SiTiCO纤维表面镀上了厚度为0.5 ~ 1.0 μm的Au涂层。研究了制备后涂层纤维与Ti基体之间的界面反应（扩散）行为，获得了从Ti基体中提取的纤维的抗拉强度。结果表明，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Ti基体的反应。这种Au_xTi_y层作为Ti和SiTiCO纤维之间的扩散屏障。提取纤维的抗拉强度仅比接收纤维低10%。界面力学性能受薄碳涂层和二氧化硅纤维表面的控制。热暴露对界面性能的影响可以忽略不计。形成的Au_xTi_y也提高了复合材料的杨氏模量。这些研究清楚地表明了金涂层用于硅纤维增强钛基复合材料的一些优势。

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.