The vast majority of our current knowledge regarding the basic mechanisms controlling irradiation effect on mechanical properties is based almost entirely on the results of post-irradiation experiments or theoretical models. However, the concurrent effects of irradiation, mechanical stress, and thermal damage on the failure phenomena of materials and components remain largely unexplored due to its internal multiscale-multiphysics coupling nature. We present here a concurrent irradiation-mechanics multiscale coupling model. The concurrent evolutions of nanoscale irradiation defect clusters, microscale dislocation configurations, and mechanical responses are well captured based on coupling cluster dynamics, discrete dislocation dynamics, and the finite element methods using an effective time marching scheme. Model predictions of defect densities and size are in general agreement with experimental observations. Irradiation hardening is shown to take place also in samples undergoing concurrent irradiation-mechanical loading, similar to samples tested post-irradiation. However, the occurrence of plastic flow localization and dislocation channel formation is not accompanied with apparent yield drop (softening) under concurrent irradiation-mechanical loading conditions, which is different from the post-irradiation case.

我们目前关于控制辐照对机械性能影响的基本机制的绝大多数知识几乎完全基于辐照后实验或理论模型的结果。然而，由于其内部的多尺度-多物理场耦合性质，辐照、机械应力和热损伤对材料和组件失效现象的同时影响在很大程度上仍未得到探索。我们在这里提出了一个并发辐照力学多尺度耦合模型。基于耦合簇动力学、离散位错动力学和使用有效时间推进方案的有限元方法，可以很好地捕捉纳米级辐照缺陷簇、微米级位错配置和机械响应的同时演变。缺陷密度和尺寸的模型预测与实验观察大体一致。与辐照后测试的样品相似，辐照硬化也发生在同时承受辐照机械载荷的样品中。然而，在同时辐照-机械载荷条件下，塑性流动局部化和位错通道形成的发生并不伴随明显的屈服下降（软化），这与辐照后的情况不同。