Simulation of low energy displacement processes in a dilute cu-au alloy

Abstract

Research into displacement cascade processes in alloy systems has received little attention, yet is potentially of interest because issues such as the effect of solutes on the displacement threshold and the defect distribution and movement in cascades are important. As part of a wider study, we have initially considered the minor substitutional solute Au in a Cu matrix, and have used molecular dynamics to investigate the properties of point defects, the threshold displacement energy E_d, and temporal and spatial distribution of defects in low-energy (≤500 eV) displacement cascades. The results show that the influence of the solute on the properties of defects is important and that E_d is dramatically different from its form in pure copper. In comparison with pure copper, the recoil of the Au solute gives rise to a higher peak at longer times in the number of displaced atoms in the generation of a displacement cascade. The influence of this on defect density in the cascade and the final number and arrangement of defects has been investigated.