Coherent phase equilibria

Some basic characteristics of phase equilibria in elastically coherent systems are reviewed. The concepts of thermodynamic fields and densities are introduced and then used in the construction of coherent phase diagrams for systems in which the elastic fields are uniform in each phase at equilibrium. The thermodynamic space in which tie lines are found is identified and application of the common-tangent construction is discussed. These ideas are then applied to binary systems in which two or three phases can exist. The existence of multiple equilibrium states for a system with a given applied stress, temperature and composition is demonstrated.