Molecular dynamics study on the Burgers vector transition of nanometric dislocation loops induced by cascade in bcc-iron

s Dislocation loops are commonly observed defects in bcc-iron based alloys under radioactive environments. They are also major sources of hardening and embrittlement in such materials. In this paper, a comprehensive molecular dynamics (MD) study is conducted concerning the effects of subsequent cascades on previously formed dislocation loops, particularly changes in their Burgers vectors induced by cascades. We reveal the atomistic mechanism behind the Burgers vector transitions and then investigate the effects of temperature, initial cluster type, loop size, and cascade parameters on the transition rate and the effects of different potentials. The competing effects of loop size and cascade energy result in an overall non-monotonic effect on the transition rate to dislocation loops, which is attributed to the density of the dissolved self-interstitial atoms in the loop. We also find temperature dependence of the transition rate of loops with M07 potential function. This study provides essential information regarding the evolution of nanometric dislocation loops under irradiation.