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通过SEM中静载动态拉伸,原位观察和研究了搅拌铸造法制备的YAl2P/Mg-Li-Al基复合材料裂纹的萌生及扩展机制。结果表明,微裂纹萌生位置主要为复合材料的铸造缺陷处、复合材料的基体中以及颗粒/基体界面处,并以在复合材料基体中萌生为主。微裂纹的扩展主要在基体和YAl2颗粒/基体界面处进行。主裂纹的长大方向具有选择性,裂纹主要沿颗粒贫化区与颗粒富集区的交界处开裂,主裂纹扩展到一定程度后,试样全面失稳而迅速断裂。基体的断裂失效在YAl2P/Mg-Li-Al复合材料拉伸断裂过程中起很大作用。
Through dynamic tensile test in SEM, the crack initiation and propagation mechanism of YAl2P / Mg-Li-Al matrix composite prepared by stirring casting method was observed and investigated in situ. The results show that the location of micro-crack initiation is mainly found in the casting defects, the matrix of the composite material and the interface of the particles / matrix, and the initiation of micro-cracks is mainly in the matrix of the composite material. The propagation of microcracks mainly occurs at the matrix and at the YAl2 particle / matrix interface. The main crack is selective to the growth direction. The crack mainly cracks along the boundary between the particle-depleted zone and the particle-enriched zone. After the main crack expands to a certain extent, the sample is completely unstably fractured and rapidly fractured. The rupture failure of matrix plays an important role in the tensile fracture of YAl2P / Mg-Li-Al composites.