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对20~#球化低碳钢金属薄膜试样在透射电镜下进行了动态拉伸试验。研究球化低碳钢对其在延性断裂过程中微空洞的形成、长大、聚合特征及其与位错的相互作用进行了研究。观察表明球化低碳钢薄膜试样的延性断裂过程仍然是微空洞的形核、长大及其聚合。从微观的尺度证实了宏观的结果。试验中观察到在裂纹扩展过程中裂纹尖端以阵发式发射大量位错,发射的位错在裂纹前沿与基体位错相互作用组成位错塞积群、位错网、位错胞等各种组态。它们都可以形成微空洞的核心。试验中还观察到以Z字形方式扩展的主裂纹两侧基体的塑变量不相互匹配,这是由于Z字形主裂纹的凹陷尖角处在钝化时发射位错的原因。由于各处发射位错的方位及数量部不同,因此塑变量也不等。
Dynamic tensile test was carried out on 20 ~ # spheroidized low-carbon steel metal film samples under transmission electron microscope. The formation, growth, polymerization characteristics and interaction between dislocations and microvoids during the ductile fracture of spheroidal mild steel were studied. The observation shows that the ductile fracture process of the spheroidized low-carbon steel film is still the nucleation, growth and polymerization of microcavity. Micro-scale confirmed the macro results. It is observed that during the crack propagation, a large number of dislocations are emitted in the form of bursts at the crack tip. The dislocations of the dislocations, the dislocation networks and the dislocation cells are caused by the interaction between the dislocations and the substrate dislocations. configuration. They all can form a micro-hollow core. It was also observed in the experiment that the plastic deformations of the matrix extending in the zigzag manner on both sides of the main crack did not match each other due to the emission dislocation during the passivation of the sharp corners of the zigzag main crack. Because of the different positions and numbers of emission dislocations, the plastic variables are not equal.