使用扫描电子显微镜和光学显微镜对ZL101铝合金的显微组织、拉伸断口及断口剖面进行了观察分析, 研究了其拉伸断裂特征。结果表明: ZL101铝合金的拉伸断口为准解理特征, 可见第二相(硅共晶体和AlFeMnSi相)沿断口分布; 裂纹在第二相粒子的尖锐和凹角处(即应力集中处)萌生, 并沿第二相扩展, 该过程会拉开(拉断)第二相粒子, 并使横向粒子产生变形; 韧窝特征是由脆性第二相被拉开后发生塑性变形产生; 舌状花样是裂纹沿一定取向晶面扩展, 并造成颗粒相变形产生; 撕裂棱是裂纹扩展至两个以一定角度相交的第二相时, 扩展方向发生较大改变产生。

Characteristics of ZL101 aluminum alloy tensile fracture were studied through observation of microstructure, tensile fracture and fracture profile by scanning electron microscopy (SEM) and optical microscopy (OM). The results indicate that the ZL101 aluminum alloy tensile fracture showed quasi-cleavage characteristic with second phases (eutectic silicon and AlFeMnSi phase) distributing along the fracture. Cracks initiated in the sharp part and concave angle of second phases where stress was concentrated, and extended along them. In this process the second phases were torn or broken, and the lateral particles deformed. Ductile deformation of the brittle phase after being torn or broken created dimples; the ligulate patterns arose when the particle phase deformed after crack expansion along certain oriented crystal faces; torn edges formed if cracks extended to two cross second phases with a certain angle and the expansion direction changed obviously.