NEW MECHANISM OF DEFECT PRODUCTION IN METALS - A MOLECULAR-DYNAMICS STUDY OF INTERSTITIAL-DISLOCATION-LOOP FORMATION IN HIGH-ENERGY DISPLACEMENT CASCADES

We present molecular-dynamics computer-simulation studies of 25-keV displacement cascades in Cu at low temperature. We observe the splitting of a cascade into subcascades and for the first time show by molecular dynamics that cascades in metals may lead to the formation of both vacancy and interstitial dislocation loops. We propose a new mechanism of defect production based on interstitial prismatic dislocation-loop formation and discuss its consequences regarding the primary state of damage in irradiated metals.