A molecular dynamics study for ultrafast process of radiation damage in materials

Abstract

Molecular dynamics calculations are performed to simulate displacement damage processes in irradiated metals. The interaction of atoms is described using the embedded atom method (EAM) potential that is modified at close atomic separation to merge smoothly with the universal ZBL-potential for description of high energy atoms. The displacement events of high energy atoms simulated here are initiated both from a single recoil atom with the kinetic energy of 20 keV in vanadium and from dimer recoil atoms of 2 keV in copper. The initial evolution of the displacement events is represented by replacement collision sequences (RCSs) and subsequent molten-structure at the center of the events. The monomer recoil event in vanadium shows a higher probability of defect production and lower probability of defect clustering, compared to the MD cascades in other metals. The dimer-recoil events in copper show a higher probability of defect clustering compared to a monomer-recoil event.