Multi-domain ordering kinetics in solid solutions under the simultaneous diffusion of solute atoms were studied. Using the example of a binary body-centered cubic alloy, a system of kinetic equations was derived which described the coupled relaxation of the occupancies of the two sub-lattices and the building of a body-centered cubic lattice by A and B species. Such an approach, supplemented by the simplest mean-field approximation, proved to be sufficient to describe both the establishment of long-range order and the segregation processes which occurred in antiphase domains. Interactions and interrelationships between the evolution of the conserved and non-conserved order parameter fields were clarified. Asymptotic and numerical analysis of the resultant evolution equations revealed a multi-stage picture of alloy relaxation. Firstly, there was a rapid development of long-range order, which was then followed by a slow redistribution of local alloy concentrations, such that the majority atoms segregated towards the region of an antiphase boundary. The alloy exhibited a distinct tendency to form a multi-domain structure from a solitary long-range order parameter fluctuation of a certain sign.

Kinetics of Coupled Ordering and Segregation in Antiphase Domains. K.Gumennyk, L.Stefanovich, E.Feldman: Physica Status Solidi B, 2009, 246[1], 56-61