Energetics of point defect interacting with bi-crystal Σ3 copper grain boundaries

Abstract

Point defects interacting with grain boundary (GB) may shed light on point defect sink strength of GB. In this work, vacancy and self-interstitial atom (SIA) formation energies within 25 Σ3 〈110〉 copper grain boundaries (GBs) were calculated using embedded atom method (EAM) potential. The energetics of point defects interacting with these GBs was analyzed. It is found that the lowest vacancy formation energies in 25 Σ3 GBs in general decrease with increasing their inclination angles with respect to Σ3 coherent twin GB (CTB). Lowest SIA formation energies in 25 Σ3 GBs except CTB, however, shows an increasing trend. The lowest vacancy within Σ3 GBs correlates well with average GB energy, but not so for SIA formation energies. Moreover, overall trend of the correlation between lowest vacancy formation energies and GB energies for Σ3 GBs and other ten GBs with Σ ranging from 5 to 13 shows a remarkable decreasing trend, but not obvious for SIA. Void denuded zone (VDZ) widths of GBs that can be used to evaluate the vacancy sink strength of them, correlates with lowest vacancy formation energies as well as average energies of GBs at their equilibrated states.