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利用钛与 B4C,石墨之间的自蔓延高温合成反应经普通的熔铸工艺原位合成制备了等摩尔 Ti C和 Ti B增强的钛基复合材料。光学金相、EPMA、TEM和 X射线衍射的研究结果表明 :存在两种不同形状的增强体 ,即短纤维状 Ti B晶须和等轴、近似等轴状 Ti C粒子。增强体与 Ti基体界面洁净 ,没有明显的界面反应。由于增强体承受载荷 ,基体合金晶粒细化以及高密度位错的存在 ,制备钛基复合材料的机械性能有了较大的提高。石墨的加入导致形成更多的等轴、近似等轴状 Ti C粒子 ,有利于改善复合材料的性能。
Titanium-based composites reinforced with TiC and TiB were prepared by in-situ synthesis by a common casting process using self-propagating high temperature synthesis reaction between titanium and B4C and graphite. The results of optical metallography, EPMA, TEM and X-ray diffraction show that there are two kinds of reinforcements with different shapes, namely short TiB whiskers and equiaxed and approximately equiaxed TiC particles. The interface between the enhanced body and the Ti matrix is clean without obvious interfacial reaction. The mechanical properties of titanium-based composites have been greatly improved due to the increase of the load on the reinforcement, the grain refinement of the matrix alloy and the existence of high-density dislocations. The addition of graphite leads to the formation of more equiaxed, approximately equiaxed TiC particles, which is beneficial to improve the properties of the composites.