The effect of migrating Σ3 {112} incoherent twin boundary on radiation tolerance of nanotwinned copper

Nanotwinned face-centered cubic metals possess superior radiation tolerance; however, the underlying mechanism of alleviating radiation damage is still under debate. In the present study, the effect of Σ3{112} incoherent twin boundary (ITB) on the radiation tolerance of nanotwinned copper was systematically investigated by the molecular dynamic simulation method. The simulation results reveal that both stacking fault tetrahedron and interstitial dislocation loop can be easily absorbed into the migrating ITB. The two types of defects occupy two different types of atom layers of the ITB and move in the opposite direction of each other, resulting in their annihilation, thus enhancing the radiation tolerance of nanotwinned copper. Another interesting finding is that the migration of ITB can be accelerated rather than retarded by both interstitials and vacancies. The above simulation results were further investigated in terms of defect formation and migration energies. The present work provides a deep insight into the radiation tolerance mechanisms of nanotwinned metals.