Modeling of microstructure evolution under cascade damage

The effects of the production of cascades on the evolution of microstructures were studied using a numerical method based on the stochastic modeling of cascade damage. Expressions are presented for the second moments of the fluctuations in the size of clusters caused by absorption of point defects shed from cascades, which provide the diffusion terms in the Fokker-Planck equations describing the evolution of clusters. This factor, combined with that of the production of residual clusters from cascades was shown to produce appreciable effects on the swelling particularly through the nucleation stage of voids. The important, but unresolved role of small clusters is discussed. (orig.)