Recent experimental work on helium-irradiated single-crystal (SC) and nano-twinned (NT) copper has shown that the formation of a helium bubble superlattice has a dramatic effect on the critical resolved shear stress of twin formation in SC copper pillars and twin migration in NT copper pillars. The mechanisms governing this dramatic change in the mechanical response of the material after helium irradiation are explained theoretically in this work. Atomistic simulations show that the presence of a helium bubble superlattice has a profound effect on twin nucleation and propagation, which are related to the mechanical responses of SC and NT copper respectively. Based on the simulations, we estimate that the bubble lattice can decrease the ideal twin nucleation stress compared to pure copper by approximately $50\text{\%}$. The modeled response of a step in a twin boundary to an applied shear stress leads to an increase in the critical resolved shear stress due to the bubble lattice. The computed increase is in qualitative agreement with experimental findings for NT copper.

最近对氦辐照单晶（SC）和纳米孪晶（NT）铜进行的实验研究表明，氦气气泡超晶格的形成对SC铜柱和孪晶中孪晶形成的临界解析剪切应力具有显着影响。在新界铜柱中迁移。在这项工作中，理论上解释了控制氦气辐照后材料机械响应中这种剧烈变化的机制。原子模拟表明，氦气气泡超晶格的存在对双晶成核和扩散具有深远的影响，这分别与SC和NT铜的机械响应有关。根据仿真，我们估计，与纯铜相比，气泡晶格可以将理想的孪晶形核应力降低大约$50\text{％}$。孪生边界中阶跃对所施加剪应力的建模响应会导致由于气泡晶格而导致的临界解析剪应力增加。计算得出的增加量与NT铜的实验结果在质量上一致。