Migration of point defects in ordered CuPt alloy during deformation

Abstract

The energy of migration of a point defect (a vacancy or an interstitial atom) in ordered CuPt alloy is determined on the basis of molecular dynamics. In CuPt alloy, copper atoms predominantly migrate. In ordered CuPt alloy, the interstitial atom forms configurations not typically seen in pure metals: the extra copper atom tends to form a crowdion along the 〈110〉 direction in the (111) plane containing copper atoms. On introducing a platinum atom, a dumbbell configuration is formed from two platinum atoms, in the direction 〈111〉 perpendicular to the (111) plane containing the platinum atoms. Migration of the interstitial atom is very anisotropic: as a rule, the interstitial atom in ordered CuPt alloy migrates along the (111) plane containing the copper atoms. In elastic extension along this plane, such anisotropy often appears in vacancy migration, while the interstitial atom migrates predominantly along the axis of extension.