Atomistic simulation of point defects in L10-type CuAu ordered alloy

The configurations of point defects and their migration mechanisms in L1(0)-type CuAu ordered alloy have been investigated with the modified analytical embedded atom method. The results show that the antisite defects Cu-Au (especially) and Au-Cu are easier to form than Cu and Au monovacancies owing to their lower formation energies. For the divacancies, the Cu-Au divacancy is the most stable configuration among the three types of configurations (Cu-Cu, Au-Au, and Cu-Au divacancies). In five migration mechanisms of either a Cu or an Au monovacancy, the antistructural bridge migration is the most favorable due to its lowest migration energy and the one next-nearest-neighbor jump (1NNNJ) migration is the most difficult mechanism but can be achieved by six nearest-neighbor cyclic jump (S[001]6NNCJ) or bent [001] six nearest-neighbor cyclic jump (B[001]6NNCJ). For a Cu monovacancy, the favorable migration mechanisms are one nearest-neighbor jump (1NNJ), B[001]6NNCJ, and S[001]6NNCJ successively; however, for an Au monovacancy, the favorable migration mechanisms are S[001]6NNCJ (or B[001]6NNCJ) and then 1NNJ. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim