Radiation-induced disordering and defect production in Cu₃Au and Ni₃Al studied by molecular dynamics simulation

We use molecular dynamics computer simulations to investigate the kinetics of disordering induced by energetic displacement cascades in two ordered intermetallics, Cu₃Au and Ni₃Al. We also study the mechanisms of defect production in these systems and compare the results to recent findings in pure metals. We employ embedded atom potentials which reproduce the main features of the phase diagram, including a disordering transition below the melting point (T_m) in Cu₃Au and an ordered compound up to T_m in Ni₃Al. We simulate events with 5 keV recoil energy in crystals containing up to 157216 atoms at 10 K. We present results of the influence of the displacement cascade on the order parameters and describe their temporal and spatial evolution. We discuss atomic mixing in the cascade regions in terms of the atomic mobilities in each sublattice. The influence of the ordering energy and the melting temperature in the behavior of the compounds is emphasized.