A SIMULATION STUDY OF THE MIGRATION AND COALESCENCE OF GAS-BUBBLES IN METALS

In this work the evolution of inert gas bubble microstructures by migration and coalescence has been simulated systematically on the basis of Smoluchowski's coagulation equations for two typical experimental conditions: (A) coarsening at constant gas content (annealing after low temperature irradiation/implantation) and (B) bubble evolution under continuous gas production at elevated temperatures (hot irradiation/implantation). The number of rate equations which had to be taken into consideration, could be limited by proper repopulation procedures. As a result of the integrations we obtain the time evolution of the bubble size distributions, the bubble densities and the mean bubble radii. We show that in the case of constant gas content, the bubble size distributions become asymptotically self-similar, whereas under continuing gas supply there is no simple scaling behaviour. In both cases the size distributions are monomodal and the asymptotic time dependences of their moments follow simple power laws. The asymptotic time dependences of the bubble densities and radii are discussed.