MOLECULAR-DYNAMICS COMPUTER-SIMULATIONS OF DISPLACEMENT CASCADES IN METALS

MD simulations of displacement cascades have become important in the study of atomic-scale processes in radiation damage. Here, we review recent advances and discuss results on a variety of processes in pure metals and alloys. The MD procedures, and the many-body interatomic potentials on which most recent simulations are based, are described, and then the general features of cascades in metals are reviewed. The ways in which the cascade state during the thermal-spike phase can be investigated are presented, and it is found that a liquid-like core is generated for cascade energies above 1 to 2 keV. This is shown to have important consequences for atomic mixing, disordering in ordered alloys, and vacancy clustering. Frenkel-pair production efficiency in the primary damage state at the end of the cascade process is found to be well below the NRT theoretical value in all the metals and alloys modelled to date. Clustering of interstitials is a persistent feature of cascade simulations for all pure metals. The mechanisms underlying these results are discussed, and it is observed that the simulations are in generally good agreement with what has been found by experiment.