LAUSR

Abstract Free surface has been recently proven effective in enabling defects reduction in heavy ion irradiated nanoporous metals. Yet to date, very little research concerns on the radiation performance of nanoporous metals under gas irradiation although gas impurities are especially deleterious leading to embrittlement and hardening problems of nuclear materials. Here, the nanoporous copper films (NPCFs) and fully dense Cu counterparts are subjected to the same He ion irradiation at room temperature. Three aspects are studied on the performance of the ion-irradiated NPCFs by the combined results of microstructure characterizations and mechanical property tests. Firstly, the pristine nanoporous structure is totally retained after He ion irradiation with slight ligament coarsening occurring only at the film surface. Secondly, He bubble reduction in size and density in nanoporous copper (NPC) ligaments is observed compared with the fully dense Cu layer. Thirdly, hardening induced by He ion irradiation in NPCFs is alleviated compared with Cu films. The free surface, serving as unsaturated defect sinks and He diffusion paths, endows the NPCFs with high resistance against He ion irradiation, which may open up an avenue of exploration for novel radiation tolerant strategies.