Radiation effects in FCC metals and intermetallic compounds: A molecular dynamics computer simulation study

摘要

We review recent results on atomic mixing, radiation-induced disordering, and defect production and clustering induced by displacement cascades in Cu, Ag, Cu(sub 3)Au and Ni(sub 3)Al. We employ molecular dynamics computer simulation methods with isotropic many body potentials and recoil energies near subcascade formation regime up the locally molten cascade core in the pure metals and intermetallics. Disordering of intermetallics takes place in the cascade core, but because of the short lifetime of the displacement cascade, chemical short range order is preserved in molten zone. Results reveal very large vacancy and interstitial type defect clusters at high recoil energy and cascade energy density. Vacancies agglomerate and collapse into Frank dislocation loops in quenching of the cascade molten core. Large interstitial clusters are directly produced in cascades and form prismatic dislocation loops. Fraction of defects in clusters for low temperature cascades increases with recoil energy and approaches (approx) 70 and 60% for interstitials and vacancies, at recoil energies near threshold for subcascades. In the case of intermetallics the large energy required to produce and transport a superdislocation appears to inhibit interstitial prismatic loop punching and interstitials appear as isolated (100) dumbbells.