A first-principles study was made of the diffusion-controlled aggregation of Frenkel defects (interstitials, vacancies) under irradiation. The necessary conditions for the efficient radiation-induced aggregation of vacancies and interstitials were determined. The calculations dealt particularly with the formation of colloids via the aggregation of similar interacting particles in the presence of a permanent (radiation-driven) source. It was shown that this process involved several intermediate stages. These were a sharp reduction in the mobility of interstitials, due to aggregation, followed by vacancy aggregation and, finally, a cooperative behavior which involved the aggregation of 2 types of defect but led to the formation of similar aggregates.

E.A.Kotomin, V.N.Kuzovkov: Materials Science Forum, 1997, 239-241, 387-90