Effects of irradiation-induced voids on confined layer slips in metallic nanolaminates

Metallic nanolaminates are promising materials for nuclear applications due to their ability to withstand extreme radiation environments by trapping irradiation-induced defects. However, the effects of irradiation-induced voids on confined layer slips (CLS) in nanolaminates remain largely unexplored. In this study, molecular dynamics simulations are employed to investigate how void size and location impact CLS in two types of Ag/Cu nanolaminates. Nanolaminated Ag and Ag single crystals are also studied as references. The results show that voids act as obstacles, significantly increasing the critical stress for dislocation glide. The void location plays a role in the critical stress but in different ways for different slip planes. The void-induced hardening is stronger on planes with lower intrinsic critical stress; as a result, adding a void homogenizes the resistance to CLS across different slip planes. Ag/Cu type II nanolaminates, where the two crystals have a "cube-on-cube" crystallographic orientation, demonstrate reduced void-induced hardening compared to type I, where two adjacent layers possess differing crystallographic orientations. In addition, some void-containing nanolaminated Ag show lower critical stress than their single-crystal line counterparts.