Interaction between disclinated non-equilibrium grain boundaries and radiation-induced interstitial/vacancy in tungsten

Abstract

Experimental works show that there are plenty of disclinated non-equilibrium grain boundaries (GBs) in polycrystalline materials obtained by the severe plastic deformation method. How these GBs affect the irradiation-induced defects is still an open question. In the present work, molecular dynamics simulation was used to investigate the interaction between disclinated non-equilibrium GBs and irradiation-induced interstitial/vacancy in tungsten. There exists a long-range stress field around the disclinated non-equilibrium GBs. Such a long-range stress field leads to strong interaction between interstitial/vacancy and the GB. The interaction energy calculations suggest that interstitial and vacancy can be attracted strongly by non-equilibrium GBs containing negative and positive disclinations, respectively. This unique interaction behavior is further confirmed by diffusion of interstitials/vacancies near these GBs. The present work clearly demonstrates that disclinated non-equilibrium GBs are stronger irradiation-induced defect sinks than their equilibrium counterparts. So increasing the proportion of disclinated non-equilibrium GBs may be an effective way to develop new-generation irradiation-resistant materials.