Experimental observations of dislocation decoration with self-interstitial atom clusters and of self-interstitial atom cluster rafts were analysed to establish the mechanisms controlling these phenomena in body-centered cubic metals. The elastic interaction between self-interstitial atom clusters, and between clusters and dislocations was included in kinetic Monte Carlo simulations of damage evolution in irradiated body-centred cubic metals. The results indicate that self-interstitial atom clusters, which normally migrate by 1D glide, rotate due to their elastic interactions, and that this rotation was necessary to explain experimentally-observed dislocation decoration and raft formation in neutron-irradiated pure Fe. The critical dose for raft formation in Fe was shown to depend upon the intrinsic glide/rotation characteristics of self-interstitial atom clusters. The model was compared with experimental observations for the evolution of defect cluster densities (sessile self-interstitial atom clusters and nano-voids), dislocation decoration characteristics and the conditions for raft formation.

Dislocation Decoration and Raft Formation in Irradiated Materials. M.Wen, N.M.Ghoniem, B.N.Singh: Philosophical Magazine, 2005, 85[22], 2561-80