Phan Anh D, Zaccone Alessio, Lam Vu D, Wakabayashi Katsunori
Faculty of Materials Science and Engineering, Computer Science, Artificial Intelligence Laboratory, Phenikaa Institute for Advanced Study, Phenikaa University, Hanoi 12116, Vietnam.
Department of Nanotechnology for Sustainable Energy, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.
Phys Rev Lett. 2021 Jan 15;126(2):025502. doi: 10.1103/PhysRevLett.126.025502.
We theoretically investigate high-pressure effects on the atomic dynamics of metallic glasses. The theory predicts compression-induced rejuvenation and the resulting strain hardening that have been recently observed in metallic glasses. Structural relaxation under pressure is mainly governed by local cage dynamics. The external pressure restricts the dynamical constraints and slows down the atomic mobility. In addition, the compression induces a rejuvenated metastable state (local minimum) at a higher energy in the free-energy landscape. Thus, compressed metallic glasses can rejuvenate and the corresponding relaxation is reversible. This behavior leads to strain hardening in mechanical deformation experiments. Theoretical predictions agree well with experiments.
我们从理论上研究了高压对金属玻璃原子动力学的影响。该理论预测了压缩诱导的年轻化以及最近在金属玻璃中观察到的由此产生的应变硬化。压力下的结构弛豫主要由局部笼状动力学控制。外部压力限制了动力学约束并减缓了原子迁移率。此外，压缩在自由能景观中诱导出一个能量更高的年轻化亚稳态（局部最小值）。因此，压缩后的金属玻璃可以年轻化，并且相应的弛豫是可逆的。这种行为在机械变形实验中导致应变硬化。理论预测与实验结果吻合良好。
