State key Laboratory of Metal Matrix Composites, School of Materials Science & Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Department of Materials Science and Engineering, Mechanical Engineering, and Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Phys Rev Lett. 2018 Mar 23;120(12):125503. doi: 10.1103/PhysRevLett.120.125503.
Shear transformation is the elementary process for plastic deformation of metallic glasses, the prediction of the occurrence of the shear transformation events is therefore of vital importance to understand the mechanical behavior of metallic glasses. In this Letter, from the view of the potential energy landscape, we find that the protocol-dependent behavior of shear transformation is governed by the stress gradient along its minimum energy path and we propose a framework as well as an atomistic approach to predict the triggering strains, locations, and structural transformations of the shear transformation events under different shear protocols in metallic glasses. Verification with a model Cu_{64}Zr_{36} metallic glass reveals that the prediction agrees well with athermal quasistatic shear simulations. The proposed framework is believed to provide an important tool for developing a quantitative understanding of the deformation processes that control mechanical behavior of metallic glasses.
剪切转变是金属玻璃塑性变形的基本过程,因此预测剪切转变事件的发生对于理解金属玻璃的力学行为至关重要。在这封信中,我们从势能景观的角度出发,发现剪切转变的协议依赖性行为是由其最小能量路径上的应力梯度决定的,我们提出了一个框架以及一种原子方法来预测在不同剪切协议下金属玻璃中剪切转变事件的触发应变、位置和结构转变。用模型 Cu_{64}Zr_{36}金属玻璃进行验证表明,预测与非热准静态剪切模拟吻合较好。相信所提出的框架将为定量理解控制金属玻璃力学行为的变形过程提供一个重要工具。