simulation of point defects and threshold displacements in pure cu and a dilute cu-凯发网

the influence of solute atoms on point-defect properties and defect generation by radiation damage in alloys is known to be important, and hence it is desirable to understand their effect on the basic mecha- nisms involved. most computer modeling of these phenomena has only considered pure metals, but as part of a project to investigate displacement cascades in alloys, we have simulated dilute solutions of gold (au) in copper (cu), treating this as a "model" for a heavy, oversized solute alloy system. in the present paper, modified many-body interatomic potentials for the cu-au system are described that are suitable for modeling high-energy atomic collisions. the properties of point defects in pure copper and the dilute alloy, including solute-defect binding energies, are presented. the oversized solute has a larger binding energy with an interstitial atom than with a vacancy. the displacement threshold energy, ea, of a cu atom and a au atom in the copper matrix has been investigated as a function of primary recoil direction, and the difference between the two species is found to be substantial. furthermore, the pres- ence of a au solute has a significant effect on the formation of frenkel pairs by the replacement- collision-sequence mechanism. these results are discussed in terms of the mass and size difference of cu and au atoms.