Prediction of multi-phase equilibria in alloy systems by the technique of successive partial equilibration

The technique of successive partial equilibria was recently employed to predict the precipitation of carbides in equilibrium with a solution phase. This involved predicting the equilibrium between a phase (the solution) whose composition could change with the overall composition of the system, and a phase which had a fixed stoichiometry with respect to the ratio of the number of atoms in the cationic sub-lattice to that in the anionic sub-lattice. This is a special case of predicting phase equilibria using this technique. In the present communication, this technique is extended to predict equilibria involving two or more phases whose compositions can vary over a range, such as that between two solutions phases. This technique is illustrated with respect to the Ag-Cu system and some salient features of the algorithm are discussed.