原位合成TiC和TiB增强钛基复合材料的微观结构与力学性能

Microstructure and mechanical properties of in situ synthesized (TiB+TiC)/Ti matrix composites

利用钛与B4C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TiC和TiB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TiB晶须和等轴、近似等轴状TiC粒子。TiB与Ti基体界面洁净 ,没有明显的界面反应 ,而TiC与Ti基体界面有非化学配比的TiC过渡层存在。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 。

TiB and TiC reinforced Ti matrix composites have been produced in situ by common casting and hot forging technology. The results of optical microscopy, EPMA, TEM and XRD show that there are two reinforcements with different shapes, namely, short fibre TiB and equiaxed or near equiaxed TiC particles. TiB whiskers were made to align along the hot forging direction after hot forging. The interface between reinforcements and Ti matrix alloy is clean. There isn't interface reaction between TiB and Ti matrix alloy, while there is non stoichiometric annuli in interface between TiC and Ti matrix alloy. The mechanical properties at room and elevated temperature of Ti matrix composites have been improved at large scale due to the following reasons: TiB whiskers and TiC particles undertaking load, refining of titanium matrix alloy'grains and high density dislocation in Ti matrix alloy.