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

研究了金属涂层对工业纯钛基单向Sitico纤维增强复合材料拉伸强度的影响。采用真空热加工方法将镀金Sitico纤维复合到工业纯钛中。Au涂层厚度为0.5~1.0μm，采用连续电沉积工艺在薄的(0.1μm)碳包覆Sitico纤维表面进行涂层。研究了制备后涂层纤维与钛基体之间的界面反应(扩散)行为，并获得了从钛基体中提取的纤维的拉伸强度。结果表明，Au涂层通过形成金属间化合物Au_xTiy有效地阻止了Sitico纤维与钛基体之间的反应，该Au_xTiy层起到了钛与Sitico纤维之间的扩散阻挡作用。抽出纤维的拉伸强度仅比原丝降低10%。界面力学性能受薄层碳涂层和Sitico纤维表面的控制。热暴露对界面性质的影响可以忽略不计。形成的Au_xTi_y还提高了复合材料的杨氏模量。研究表明，Au涂层在Sitico纤维增强钛基复合材料中具有一定的优势。

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.