The formation and evolution of point and line defects in irradiated materials were analyzed. The effects of irradiation were described by using dynamic conservation equations for 2 mobile atomic species (vacancies, interstitials) and for 2 essentially immobile microstructural elements (vacancy and interstitial clusters). It was shown that, under certain conditions, uniform vacancy and interstitial cluster populations became unstable and formed large-scale spatially organized distributions. The structure and symmetry of the latter changed with time. The selection and stability of the resultant microstructure were studied in the weakly non-linear regime around the bifurcation point. It was shown that point defect recombination did not affect the long-term evolution of the microstructure, and that the final pattern would correspond to a planar wall structure; as observed experimentally. A time-dependent evolution of the self-organized microstructure was demonstrated for various irradiation and temperature conditions, and particular emphasis was placed upon the role of dislocation bias and direct cascade clustering on the self-organization of extended defects.

D.Walgraef, N.M.Ghoniem: Physical Review B, 1995, 52[6], 3951-62