Yu Li, Wang Tzu-Chiang
State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, China.
School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2019 Aug 29;9(1):12554. doi: 10.1038/s41598-019-49085-1.
The Mohr-Coulomb (M-C) stress criterion is widely applied to describe the pressure sensitivity of bulk metallic glasses (BMGs). However, this criterion is incapable of predicting the variation in fracture angles under different loading modes. Moreover, the M-C criterion cannot describe the plastic fracture of BMGs under compressive loading because the nominal stress of most BMGs remains unchanged after the materials yield. Based on these limitations, we propose a new generalized M-C strain criterion and apply it to analyze the fracture behaviors of two typical Zr-based BMG round bar specimens under complex compressive loading. In this case, the predicted initial yielding stress is in good agreement with the experimental results. The theoretical results can also describe the critical shear strain and fracture angle of BMGs that are associated with the deformation mode.
莫尔-库仑（M-C）应力准则被广泛应用于描述块状金属玻璃（BMG）的压力敏感性。然而，该准则无法预测不同加载模式下断裂角的变化。此外，M-C准则不能描述BMG在压缩加载下的塑性断裂，因为大多数BMG材料屈服后名义应力保持不变。基于这些局限性，我们提出了一种新的广义M-C应变准则，并将其应用于分析两种典型的Zr基BMG圆棒试样在复杂压缩加载下的断裂行为。在这种情况下，预测的初始屈服应力与实验结果吻合良好。理论结果还可以描述与变形模式相关的BMG的临界剪切应变和断裂角。
