Trapping of irradiation-induced defects in the vicinity of disclinated non-equilibrium grain boundaries in tungsten

Abstract

Disclinated non-equilibrium grain boundaries (GBs) exist extensively in metals fabricated through severe plastic deformation; however, their effect on the behavior of radiation-induced defects is rarely studied and remains unclear. In the present work, we employed molecular dynamics simulations to investigate the behavior of interstitial/vacancy type defects in the vicinity of disclinated non-equilibrium GBs in tungsten. The simulation results reveal that disclinated non-equilibrium GBs have a strong attraction effect on the defects, and therefore induce these defects to migrate towards them. Sometimes the defects can be trapped at certain sites around the GBs and sway here, and occasionally they can escape from the trapping sites with the aid of thermal activation or rotation, thus continuing to migrate toward the GBs. The simulation results were further discussed systematically in terms of stress and energy. This work provides us a new insight into the effect of GBs on the behavior of radiation-induced defects.