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采用放电等离子烧结 (SPS)技术 ,制备了质量分数为10 %的TiC/TiAl复合材料 ,从微观结构上研究了TiC颗粒对TiAl基体材料力学性能的影响。实验结果表明 :在TiC/TiAl复合材料中TiC颗粒主要分布于晶界 ,少量进入基体晶粒的内部 ,形成晶内型结构 ;TiC颗粒的引入细化基体晶粒的尺寸 ,有效地阻碍材料内部裂纹扩展 ,引起裂纹偏转 ,增加其扩展路径 ,改善材料的韧性 ,同时在晶界和晶内形成了一系列位错。位错强化与细晶强化是主要的强化机制 ,TiC/TiAl复合材料韧性的提高主要源于TiC粒子对裂纹的偏转
TiC / TiAl composites with mass fraction of 10% were prepared by spark plasma sintering (SPS) technique. The effects of TiC particles on the mechanical properties of TiAl matrix were investigated microstructurally. The experimental results show that the TiC particles are mainly distributed in the grain boundaries and slightly enter into the matrix grains in the TiC / TiAl composites. The TiC particles are refined to reduce the size of the matrix grains and effectively hinder the inner part of the material Crack propagation causes the crack to deflect, increasing its propagation path and improving the toughness of the material. At the same time, a series of dislocations are formed in grain boundaries and grains. Dislocation strengthening and fine grain strengthening are the main strengthening mechanisms. The increase of toughness of TiC / TiAl composites is mainly due to the deflection of TiC particles