Molecular dynamics simulations of displacement cascades in nanotwinned Cu

With large-scale molecular dynamics simulations, we investigate systematically displacement cascades in nanotwinned Cu with different twin spacings. Coherent twin boundaries (CTBs) are proven to be effective defect sinks, and they exhibit preferential absorption of interstitials. The existence of twin boundary affected zone is confirmed, and its width depends on the energy of primary knock-on atom. When stacking fault tetrahedra nucleate near CTBs, their growth are suppressed, resulting in truncation. CTB migration is observed, which is induced by transient internal stress arising from collision cascades.