Monte Carlo computer simulation of order-order kinetics in the L12-ordered Ni3Al binary system -: art. no. 174109

The results of previous extensive experiments on gamma'-Ni3Al systems are interpreted and explained by means of Monte Carlo computer simulations based on the Glauber algorithm for vacancy mechanism of atomic migration in a superstructure. The complex character of the experimental "order-order" relaxation curves, as well as the theoretically predicted effect of vacancy ordering have been perfectly reproduced and analyzed in detail in terms of the dynamics of particular kinds of atomic jumps. The relaxations corresponding to an increase and decrease of the degree of long-range order showed up as processes only partially symmetric in time. The proposed model scenario for the creation and elimination of antisite atoms in the relaxing L 1(2)-type superstructure shows that the experimentally observed features of the "order-order'' processes in Ni3Al follow from an interplay between two dominating and coupled modes of long- and short-range ordering.