SiC/AZ91D镁基复合材料单轴拉伸过程中裂纹萌生扩展机制

Crack initiation and propagation mechanism of SiC/AZ91D magnesium matrix composites during uniaxial tension

利用Abaqus有限元分析软件研究了不同体积分数和不同形状颗粒的SiC/AZ91D镁基复合材料在单轴拉伸下的裂纹萌生、扩展以及断裂机制。结果表明,圆形颗粒SiC/AZ91D镁基复合材料的屈服强度为248 MPa,正方形颗粒SiC/AZ91D镁基复合材料的屈服强度为190 MPa,原始形状颗粒镁基复合材料的屈服强度为210 MPa。颗粒体积分数为10%、15%和20%的复合材料裂纹断裂时间分别在施载后的第40、第33和第31μs。圆形颗粒复合材料的裂纹扩展机制是基体损伤萌生的裂纹扩张导致材料断裂,而正方形颗粒复合材料和原始形状颗粒复合材料的裂纹扩展机制是颗粒与基体交界处萌生裂纹,导致主裂纹形成并产生次生裂纹扩张直至材料断裂。

The crack initiation,propagation and fracture mechanism of SiC/AZ91D magnesium matrix composites with different volume fractions and different particle shapes under uniaxial tension were studied by Abaqus finite element analysis software.The results show that the yield strength of circular particle SiC/AZ91D magnesium matrix composites is 248 MPa,the yield strength of square particle SiC/AZ91D magnesium matrix composites is 190 MPa,and the yield strength of original-shaped particle magnesium matrix composites is 210 MPa.The crack fracture time of composites with particle volume fraction of 10%,15%and 20%is at 40,33 and 31μs,respectively.The crack propagation mechanism of circular particle composites is the material fracture,which is caused by crack propagation initiated by matrix damage,while the crack propagation mechanism of square particle composites and original-shaped particle composites is the crack initiation at the interface between particles and matrix,which leads to the formation of main crack and secondary crack propagation until material fracture.