SiC／Al复合材料的微观结构对裂纹扩展的影响

Effects of Microstructure to Cracking and Propagating in SiC/Al Composite Material

借助高倍光学显微镜和扫描电子显微镜，研究了ＳｉＣ颗粒体积分数分别为０．１和０．２的ＳｉＣ／Ａｌ复合材料单边缺口试样拉伸断裂过程中材料的微观结构对细观裂纹扩展的影响。结果表明：对复合材料中原有微缺口的敏感性，前者比后者高；导致产生断裂裂纹的细观裂纹的萌生、扩展行为不仅受宏观主应力的影响，而且受细观裂纹尖端前方的微观组织结构的控制。细观裂纹尖端前方的ＳｉＣ颗粒既能抑制裂纹扩展，又能改变裂纹扩展的微观路径；而微观结构缺陷既增加了裂纹的扩展，也改变了裂纹扩展的微观方向；细观裂纹的扩展是不均匀的。

This paper investigates the effects of microstructures to the initiation and propagation of cracks in SiCparticle Al composite materials by optical microscope and scanning electron microscope,10% and 20% volume percentages SiC_p/Al composite are usedResults show that the 10% volume percentage SiC_p/Al is more sensitive to the micro-notch than the 20%one. The cracking and propagating behavior are not only affected by themacroscopic remote stresses, but also controlled by microstructures ahead of the crack. SiC particle defects can either prohibit crack propagation,or change the cracking path.Microstructural defects can increase crack growth rates,The propagation is non-uniform.