Point defect properties in the vicinity of an Al/U interface

Abstract

The static and dynamic properties of vacancies and interstitials have been studied in the neighbourhood of a (1 1 1)Al/(0 0 1)aU interface using classical atomistic techniques. A suitable interatomic EAM potential for the U–Al system have been used for this purpose. To characterize their properties far from the interface, the same defects have also been studied in bulk Al and aU. We observe that point defect stability depends on both distance and zone on the interface plane where it is created and have their minimum formation energy in the first interface layers. Point defects generated beyond the third plane on each phase recover their corresponding bulk value. Regarding vacancy migration, only jumps in the first few layers around the interface are studied. Results show that the vacancy in aU exchanges faster with Al impurities than with most U atoms while the opposite behaviour is observed in Al. All these results suggest a faster diffusion of Al in aU than vice versa in agreement with the experiments.