Molecular dynamics simulations of displacement cascade and threshold energy in ordered alloy Al3U
W Yang and PH Chen and WS Lai and ZJ Zhang, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 449, 22-28 (2019).
The displacement threshold energy and collision cascades in ordered alloy Al3U with L1(2) structure are studied by molecular dynamics simulations. It turns out that as compared with Al recoils, U primary recoils generally have a lower average displacement threshold energy E-d (i.e. 41 eV vs 20 eV) and show less crystallographic anisotropy. The 1 1 0 direction which can produced a...-U-Al-U-Al... replacement collision sequence is found to have a high E-d, but does not create a long antisite defect chain. We have simulated 100 cascades with different energies of primary knock-on atom (PKA) ranging from 1 to 5 keV to make clear which role the energy, direction and PKA's species has played on defect production. The number of surviving stable defects has a power-law dependence on energy. Displacement cascades tend to form large size clusters involving many point defects with increasing PKA's energy, and the U PKA generally forms clusters with size larger than the Al recoil.
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