TiC/TiAl复合材料微观结构观察及强韧化机理分析

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。

Obsvervation of microstructure of TiC/TiAl cemposites and the analysis of strengthening and toughehing mechanisms

TiC/TiAl composites with 10%(wt) TiC additive were fabricated by the rapid heating technology of spark plasma sintering (SPS).The influence of TiC produced on the mechanical properties of TiAl intermetallics was investigated from the microstructure.The results indicated:the particles of TiC primarily were distributed around the boundary of TiAl matrix and few particles of TiC entered into the inside of TiAl particles.The distribution of TiC particles inevitably formed a series of dislocations along the boundary of TiAl or inside TiAl particles;meanwhile the particles TiC could significantly refine the grain size of matrix and cumber the extension of crackes.Due to the deflection of crackes,their extending paths were added which was beneficial to the improvement of materials' toughness.The main strengthening mechanisms were due to refining matrix and dislocation strengthening while the deflection of crackes because of TiC particles contributed to the improvement of TiC/TiAl composites' toughness.