A molecular dynamics simulation study of displacement cascades in vanadium

Molecular dynamics calculations were performed to simulate the primary stat e of radiation damage processes in vanadium. The interaction of atoms was d escribed by the embedded atom method (EAM) potential that was modified at c lose atomic separation to merge smoothly with the universal ZBL-potential f or description of the higher energy recoils in cascades. The initial develo pment of displacement cascades was observed to consist of replacement colli sion sequences (RCSs) and subsequent molten structures at the centers of ca scades. We evaluated the efficiencies of defect production in the displacem ent events initiated from recoils with kinetic energies of up to 20 keV. Th e Frenkel pair production is found to have a power-law dependence on the pr imary recoil energies. The energy dependence is obviously different between single and multiple Frenkel pair production. The efficiencies of defect pr oduction and cascade mixing are somewhat higher and lower in bcc vanadium c ascades, respectively, than those of fee metals. (C) 1999 Elsevier Science B.V. All rights reserved.