Radiation damage mitigation in nanostructured metals

High energy neutron and heavy ion radiation cause microstructural and mechanical degradation in metals and alloys, such as high density defect, phase segregation, void swelling, embrittlement and creep. Radiation induced damages typically limit nuclear materials to a lifetime of about 40 years while next generation fission reactors require materials that can sustain over 60 - 80 years. Therefore it is of great significance to explore new materials with better radiation tolerance. Nanostructured metals are promising in this case because of their possession of high volume fraction of interfaces, which are effective sinks for radiation induced defects. The goal of this study is to study the radiation responses of several nanostructured metallic thin film systems, including Ag/Ni multilayers and nanotwinned Ag.

Ex situ and in situ radiation responses in these nanostructured metals reveal that dissimilar layer interfaces absorb irradiation induced defect clusters and alleviate radiation hardening. Coherent twin boundaries can interact with stacking fault tetrahedral and remove them effectively. Twin boundaries can actively absorb radiation induced defects and defect clusters resulting in boundary migration.