The evolution of the damage produced by collision cascades in Fe was studied using kinetic Monte Carlo and rate-theory approaches. The initial damage distribution was deduced from molecular dynamics simulations of 30keV recoils in Fe. Isochronal annealing was simulated in order to identify the various thermally activated mechanisms that governed defect evolution. When clusters formed during collision cascades, kinetic Monte Carlo simulations showed that additional recovery peaks should be expected, when compared to the recovery curves obtained under electron irradiation conditions. Detailed kinetic Monte Carlo and rate-theory simulations revealed that some of these recovery peaks were due to correlated recombination, at low temperatures, between defects. In particular, it was shown that, under cascade-damage conditions, it was possible to observe correlated recombination between vacancies and self-interstitial clusters. These correlated recombinations could not be reproduced by a rate-theory model and, therefore, the kinetic Monte Carlo and rate theory differed at low temperatures. However, under the present conditions, the contribution from correlated recombination was very small and no significant differences were therefore observed, at high temperatures, between these 2 models.

Simulation of Defect Evolution in Irradiated Materials - Role of Intracascade Clustering and Correlated Recombination. C.J.Ortiz, M.J.Caturla: Physical Review B, 2007, 75[18], 184101 (11pp)