Transient ordered states in phase-separating alloys

We demonstrate the existence of transient ordered phases in alloys which, at equilibrium, exhibit a definite tendency toward segregation. This is shown through a Monte Carlo study of the decomposition kinetics of a bcc TiV alloy based on first-principles electronic structure calculations. Specifically, we predict a transient B32 ordering of the quenched-in solid solution before separation into Ti- and V-rich disordered phases. We discuss the requirements for such unusual behavior in relation to experiment, and compare Monte Carlo results for a 2D model system with mean-field predictions.