Evaluation of time-dependent void nucleation theory under ion bombardment conditions

The applicability of a steady state and time-dependent homogeneous void nucleation theory to charged-particle irradiation experiments was investigated. The steady-state theory was found to be inappropriate, since significant changes in a metal's microstructure would likely occur before the void nucleation rate could reach steady state. Two types of time dependence were examined, that of the point defect concentrations at the beginning of an irradiation and the longer-term time dependence of void nucleation. It was found that vacancy and interstitial clustering significantly reduce the relaxation time for the point defect concentrations. An efficient form of time-dependent homogeneous nucleation theory was applied to ion bombardment conditions to predict void size distributions