原位合成TiC/Ti基复合材料增强体的生长机制

GROWTH MECHANISM OF REINFORCEMENT IN IN SITU PROCESSED TiC/Ti COMPOSITES

利用Ｔｉ与Ｃ之间的自蔓延高温合成反应，经非自耗电弧熔炼工艺制备了ＴｉＣ增强的Ｔｉ基复合材料借助Ｘ射线衍射（ＸＲＤ）和光学金相显微镜分析了复合材料的物相和增强体的形态结果表明：复合材料由ＴＩＣ增强体和基体Ｔｉ合金组成．而原位合成增强体的形貌与凝固过程密切相关，ＴｉＣ增强体易长成树枝晶和等轴颗粒形状．Ａｌ元素的加入不仅固溶强化了Ｔｉ合金基体，同时通过对凝固过程的影响，使ＴｉＣ增强体更为细小，并趋向于长成等轴状粒子．

TiC reinforced titanium matrix composites have been produced by non-consumablearc-melting technology utilizing the self-propagation high--temperature synthesis reaction between tita-nium and carbon. Phase identification and reinforcements morphologies observation have been performedby XRD and optical microscopy. The results show that there only exist two phases in the composites,namely TiC reinforcement and titanium matrix alloy. Reinforcements' morphologies are closely relate tothe solidification paths, TiC reinforcements airs liable to grow as dendritic and equiaxed particles. The ad-dition of aluminum element not only strengthens the titanium matrix alloy by solid solution strengthening,but also exercises effects on solidification paths which result in more fine TiC reinforcements and make TiCreinforcements grow as equiaxed particles easily.