Modification on theory of sink strength: An Object Kinetic Monte Carlo study

Abstract

Sink strength is a fundamental quantity in modeling the microstructure evolution of irradiated materials by the mean-field approaches. The analytical expressions for different sinks have been extensively studied. The Object Kinetic Monte Carlo (OKMC) simulations were subsequently performed to corroborate the expressions and to guide the development of analytical theories. Although a general agreement was found between the theory and simulation, there are still some discrepancies in the case of the small spherical sinks and the dislocation lines. In this work, OKMC simulations were performed to study the sink strength of spherical sinks and dislocation lines. Our results revealed the origins of discrepancies between the theory and simulation for small sinks, high volume fraction sinks and periodically distributed dislocation lines. The theoretical corrections were also proposed accordingly. These corrections can extend the capabilities of mean-field approaches to properly reproduce the defect evolution of irradiated materials, and provide a better insight into the experimental phenomena, such as the defect cluster nucleation, the irradiation-induced swelling and the blistering.