Interactions between vacancy and glissile interstitial clusters in iron and copper

Reactions between defect clusters and point defects are the main mechanism of clusters growth and shrinkage under different conditions and therefore they are necessary input of any model for prediction of microstructure evolution. Traditionally such reactions are treated as the evolution of size distribution of defect clusters where the change in size is considered to be a simple reaction independent of the atomic structure. For example, the interaction between a vacancy and a self-interstitial cluster is treated as an annihilation reaction. However, recent atomistic studies have demonstrated that such reactions could be more complicated. In this paper, we present the results of atomic level modelling of the interaction between clusters of self-interstitial atoms (SIAs) and a vacancy in fcc Cu and bcc Fe. It is shown that vacancies annihilate only with interstitials at the cluster edge. Vacancies inside the cluster glide prism do not recombine but prevent cluster mobility. There are significant differences in the interaction related to the differences in the atomic structure of clusters in particular metals.