Low-dose neutron irradiation damage in copper-germanium alloys

Abstract

Abstract A transmission-electron-microscopy study has been made of early stages in the development of irradiation damage in copper-germanium alloys irradiated at temperatures from 355 K to 623 K to fast neutron doses between 1021 n m−2 and 2 × 1022 n m−2 (E > 1 MeV). The various components of the damage microstructures are analysed in order to investigate the effects of alloying at different irradiation temperatures and doses. The damage observed in specimens irradiated at 355 K consisted of a homogeneous distribution of small (< 15 nm) vacancy and interstitial loops. While the vacancy-loop population appeared relatively insensitive to Ge content, the concentration of interstitial loops increased and their sizes decreased with increasing Ge content. This is attributed to a decrease in interstitial mobility caused by solute-interstitial trapping. The damage in alloys irradiated at temperatures ≥ 523 K was generally inhomogeneous in the more dilute alloys (< 1% Ge). ‘High-damage regions’ (HDR) consisting of...