MONTE-CARLO STUDY OF THE GROWTH OF L1(2)-ORDERED DOMAINS IN FCC A(3)BBINARY-ALLOYS

A Monte Carlo study of the late time growth of L1(2)-ordered domains i n a fee A(3)B binary alloy is presented The energy of the alloy has be en modeled by a nearest-neighbor interaction Ising Hamiltonian. The sy stem exhibits a fourfold degenerated ground state and two kinds of int erfaces separating ordered domains: flat and curved antiphase boundari es. Two different dynamics are used in the simulations: the standard a tom-atom exchange mechanism and the more realistic vacancy-atom exchan ge mechanism. The results obtained by both methods are compared. In pa rticular we study the time evolution of the excess energy, the structu re factor and the mean distance between walls. In the case of atom-ato m exchange mechanism anisotropic growth has been found: two characteri stic lengths are needed in order to describe the evolution. Contrarily , with the vacancy-atom exchange mechanism scaling with a single lengt h holds. Results are contrasted with existing experiments in Cu3Au and theories for anisotropic growth.