Body center cubic iron materials are commonly used in nuclear power plants. In bcc-iron, symmetric tilt grain boundaries (STGBs), which are believed to play important roles on self-healing, are susceptible to configuration and structural change under irradiation. The effect of such changes on mechanical properties of such GBs is still unknown. In this work, using molecular dynamics simulations, we find that the critical shear stress ${\tau }_c$ required for $\text{Σ}5$ STGB migration is greatly reduced by either displacement cascade nearby or absorption of defect clusters. Moreover, we find that the trapping of radiation-induced interstitial-type dislocation loops could also decrease ${\tau }_c$, indicating that displacement cascades could also exert a long-range effect on GBs due to the fast diffusion of interstitial clusters.

体心立方铁材料通常用于核电站。在bcc铁中，对称的倾斜晶界（STGB）被认为对自我修复起着重要作用，在辐照下容易发生构型和结构变化。此类变化对此类GB力学性能的影响仍然未知。在这项工作中，使用分子动力学模拟，我们发现临界剪切应力${\tau }_C$ 需要 $\text{Σ}5$STGB迁移可以通过附近的位移级联或缺陷簇的吸收而大大减少。此外，我们发现辐射诱导的间隙型位错环的陷获也可以减少${\tau }_C$，表明位移级联也可能由于间隙簇的快速扩散而对GBs产生长期影响。