HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, United Kingdom.
Bristol Centre for Complexity Science, University of Bristol, Bristol BS8 1TS, United Kingdom.
Phys Rev E. 2018 Mar;97(3-1):032609. doi: 10.1103/PhysRevE.97.032609.
We consider the yielding under simple shear of a binary Lennard-Jones glass former whose super-Arrhenius dynamics are correlated with the formation of icosahedral structures. We recast this glass former as an effective system of icosahedra [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424]. Looking at the small-strain region of sheared simulations, we observe that shear rates affect the shear localization behavior particularly at temperatures below the glass transition as defined with a fit to the Vogel-Fulcher-Tamman equation. At higher temperature, shear localization starts immediately on shearing for all shear rates. At lower temperatures, faster shear rates can result in a delayed start in shear localization, which begins close to the yield stress. Building from a previous work which considered steady-state shear [Pinney et al., J. Chem. Phys. 143, 244507 (2015)JCPSA60021-960610.1063/1.4938424], we interpret the response to shear and the shear localization in terms of a local effective temperature with our system of icosahedra. We find that the effective temperatures of the regions undergoing shear localization increase significantly with increasing strain (before reaching a steady-state plateau).
我们考虑了二元 Lennard-Jones 玻璃形成体在简单剪切下的屈服，其超 Arrhenius 动力学与二十面体结构的形成相关。我们将这种玻璃形成体重新表述为二十面体的有效体系[Pinney 等人，J. Chem. Phys. 143, 244507（2015）JCPSA60021-960610.1063/1.4938424]。在剪切模拟的小应变区域，我们观察到剪切率影响剪切局部化行为，特别是在玻璃化转变温度以下，该温度通过对 Vogel-Fulcher-Tamman 方程的拟合来定义。在较高温度下，所有剪切率下的剪切局部化都会立即开始。在较低温度下，较快的剪切率可能导致剪切局部化的开始延迟，这始于接近屈服应力的位置。基于先前考虑稳态剪切的工作[Pinney 等人，J. Chem. Phys. 143, 244507（2015）JCPSA60021-960610.1063/1.4938424]，我们用我们的二十面体体系来解释剪切响应和剪切局部化。我们发现，经历剪切局部化的区域的有效温度随着应变的增加而显著增加（在达到稳态平台之前）。
