A MOLECULAR-DYNAMICS STUDY FOR ULTRAFAST PROCESS OF RADIATION-DAMAGE IN MATERIALS

Molecular dynamics calculations are performed to simulate displacement damage processes in irradiated metals. The interaction of atoms is de scribed using the embedded atom method (EAM) potential that is modifie d at close atomic separation to merge smoothly with the universal ZBL- potential for description of high energy atoms. The displacement event s 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 di mer recoil atoms of 2 keV in copper. The initial evolution of the disp lacement events is represented by replacement collision sequences (RCS s) and subsequent molten-structure at the center of the events. The mo nomer recoil event in vanadium shows a higher probability of defect pr oduction and lower probability of defect clustering, compared to the M D cascades in other metals. The dimer-recoil events in copper show a h igher probability of defect clustering compared to a monomer-recoil ev ent. (C) 1997 Elsevier Science B.V.