Low-dose neutron irradiation damage in copper

Abstract

Abstract Transmission electron microscopy has been used to follow how the damage structure as a whole evolves from the earliest stages (1021-2 × 1022 n m−2 (E > 1 MeV)) in neutron-irradiated copper over a range of temperatures from 523 to 623 K. A major feature was the observation of an inhomogeneous structure from the lowest doses consisting of high- and low-damage regions. At 523 K the high-damage regions (HDR) were particularly well developed and consisted of tangles of dislocations decorated by interstitial and vacancy dislocation loops, which grew in size as the dose increased. At 573 and 623 K the HDR were more widely spaced, with the constituent dislocations being relatively unjogged, loosely tangled and not decorated by dislocation loops. The relatively undamaged regions between the coarse dislocation structure (LDR) contained small dislocation loops, stacking-fault tetrahedra (SFT) and/or voids. The defect types depend on neutron dose and irradiation temperature. At 623 and 573 K SFT and voids co...