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利用透射电镜拉伸台技术对Ａｌ２Ｏ３基复合材料的动态断裂行为进行原位观 察。实验结果显示，Ａｌ２Ｏ３短纤维增强Ａｌ－１２Ｓｉ复合材料在断裂行为的细节上与其它Ａｌ基 复合材料有所不同，它除在基体中可萌生微裂纹并扩展外．纤维／基体界面也是重要的裂纹源 及扩展路径，同时还发现裂纹在纤维薄弱处形核、扩展引起纤维断裂。导致这一结果的原因 可能在于，一是纤维／基体界面结合较弱，增加了界面开裂的几率，二是该复合材料纤维平均 长度大于其临界纤维长度，外加载荷可有效地从基体通过纤维／基体界面传递到纤维上来，当 纤维存在结构缺陷时会引起纤维的破坏。
The dynamic fracture behavior of Al2O3-based composites was observed by transmission electron microscopy (TEM). The experimental results show that the Al-12Si composite reinforced with Al 2 O 3 staple fibers is different from other Al matrix composites in the fracture behavior in detail, except that it can initiate micro-cracks in the matrix and expand. The fiber / matrix interface is also an important source of cracks and propagation pathways. At the same time, it is also found that the nuclei are cracked at the weakness of the fiber, leading to the fracture of the fiber. The reason for this may be that firstly, the fiber / matrix interface is weak and increases the probability of interface cracking; secondly, the average length of the composite fiber is greater than its critical fiber length, and the applied load can effectively pass from the substrate through the fiber / The substrate interface is transferred to the fiber, causing fiber failure when the fiber is structurally defective.