The influence of strain amplitude, glass stability and thermal fluctuations on shear band formation and yielding transition is studied using molecular dynamics simulations. The model binary mixture is first gradually cooled below the glass transition temperature and then periodically deformed to access a broad range of potential energy states. We find that the critical strain amplitude becomes larger for highly annealed glasses within about one thousand shear cycles. Moreover, upon continued loading at a fixed strain amplitude, the yielding transition is delayed in glasses mechanically annealed to lower energy states. It is also demonstrated that nucleation of a small cluster of atoms with large nonaffine displacements precedes a sharp energy change associated with the yielding transition. These results are important for thermal and mechanical processing of amorphous alloys with tunable mechanical and physical properties.

使用分子动力学模拟研究了应变幅度，玻璃稳定性和热波动对剪切带形成和屈服转变的影响。首先将模型二元混合物逐渐冷却至玻璃化转变温度以下，然后定期变形以获取广泛的势能状态。我们发现，在约一千个剪切循环内，高度退火的玻璃的临界应变幅度变大。此外，在以固定的应变幅度继续加载时，在机械退火至较低能量状态的玻璃中，屈服转变会延迟。还证明了具有大非仿射位移的小原子簇的成核先于与屈服跃迁相关的急剧能量变化。