Fan Beibei, Li Maozhi
Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China.
Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China.
Materials (Basel). 2024 May 23;17(11):2507. doi: 10.3390/ma17112507.
Tensile tests were performed on CuZr metallic glass at strain rates of 10/s, 10/s, and 10/s via classical molecular dynamics simulations to explore the underlying mechanism by which strain rate affects deformation behavior. It was found that strain rate has a great impact on the deformation behavior of metallic glass. The higher the strain rate is, the larger the yield strength. We also found that the strain rate changes the atomic structure evolution during deformation, but that the difference in the atomic structure evolution induced by different strain rates is not significant. However, the mechanical response under deformation conditions is found to be significantly different with the change in strain rate. The average von Mises strain of a system in the case of 10/s is much larger than that of 10/s. In contrast, more atoms tend to participate in deformation with increasing strain rate, indicating that the strain localization degree is more significant in cases of lower strain rates. Therefore, increasing the strain rate reduces the degree of deformation heterogeneity, leading to an increase in yield strength. Further analysis shows that the structural features of atomic clusters faded out during deformation as the strain rate increased, benefiting more homogeneous deformation behavior. Our findings provide more useful insights into the deformation mechanisms of metallic glass.
通过经典分子动力学模拟，在应变速率为10⁻³/s、10⁻²/s和10⁻¹/s的条件下对CuZr金属玻璃进行拉伸试验，以探究应变速率影响变形行为的潜在机制。研究发现，应变速率对金属玻璃的变形行为有很大影响。应变速率越高，屈服强度越大。我们还发现，应变速率会改变变形过程中的原子结构演化，但不同应变速率引起的原子结构演化差异并不显著。然而，发现在变形条件下的力学响应随应变速率的变化而显著不同。在10⁻¹/s情况下系统的平均冯·米塞斯应变远大于10⁻³/s时的情况。相反，随着应变速率增加，更多原子倾向于参与变形，这表明在较低应变速率情况下应变局部化程度更显著。因此，增加应变速率会降低变形不均匀程度，导致屈服强度增加。进一步分析表明，随着应变速率增加，原子团簇的结构特征在变形过程中逐渐消失，有利于更均匀的变形行为。我们的研究结果为金属玻璃的变形机制提供了更有用的见解。
