Fracture morphology pattern transition dominated by the crack tip curvature radius in brittle metallic glasses
Fracture morphology pattern transition dominated by the crack tip curvature radius in brittle metallic glasses
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DOI：
10.1016/j.msea.2014.08.060
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发表时间：
2014-11
期刊：
影响因子：
6.4
通讯作者：
M. Gao;D. Ding;Dongshan Zhao;H. Bai;Wen-Qiong Wang
中科院分区：
文献类型：
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作者：
M. Gao;D. Ding;Dongshan Zhao;H. Bai;Wen-Qiong Wang
采用扫描电镜（SEM）和原子力显微镜（AFM）对脆性镁基金属玻璃断口不同断裂形态的动态演化进行了系统定量的研究。结果表明，断裂形态的演化受临界裂纹尖端曲率半径这一有效动态参数的支配。基于裂纹尖端塑性区和剪切转变区（STZ）理论，提出了考虑STZ活化的裂纹尖端曲率半径演化的理论模型。该模型可以模拟脆性mg合金的裂纹扩展过程，预测脆性mg合金的临界裂纹尖端曲率半径以及韧窝与周期性波纹之间的断裂模式转变。这些结果对认识mggs微观断裂机制和断裂的构造成因具有重要意义。
The dynamic evolutions of different fracture morphologies in the fracture surface of brittle Mg-based metallic glasses (MGs) were systematically and quantitatively studied by SEM and AFM. It shows that the evolution of the fracture morphology pattern is dominated by an effective dynamic parameter of critical crack tip curvature radius. Based on crack tip plastic zone and shear transformation zone (STZ) theories, a theoretical model for the evolution of the crack tip curvature radius by considering the activation of STZs during fracture was proposed. The model can simulate the crack propagation process, and predict the critical crack tip curvature radius and the fracture pattern transition between the dimples and the periodic corrugations solely occurring in brittle MGs. These results have implications for understanding the microscopic fracture mechanism and the structural origin of fracture in MGs.