The Concept of Production Bias and Its Possible Role in Defect Accumulation under Cascade Damage Conditions

Abstract

AbstractIn the study of microstructural evolution and macroscopic property changes due to radiation damage, the point defects are usually modelled as being produced continuously in time and uniformly in space. Furthermore, the excess of vacancies required to sustain the void growth is assumed to arise entirely due to the preferential trapping of interstitial atoms at dislocations. It is shown that this approach may not be appropriate for cascade damage conditions where both vacancies and interstitials are produced in a highly localized and segregated fashion. A model is presented which takes into account the effects of both, vacancy and interstitial clustering in the cascade zones on the defect accumulation rate (e. g. swelling rate) under cascade damage conditions. The consideration of interstitial clustering in the cascade yields a production bias which is found to be a potent driving force for void swelling in addition to the one provided by the dislocation bias.