Contribution of matrix frustration to the free energy of cluster distributions in binary alloys

A generalized version of Frenkel's model of a cluster gas is proposed to provide a rigorous description of the contribution of the configuration entropy to the total free energy of cluster distributions in a binary alloy. It is shown that the predicted cluster distributions are in excellent agreement with those obtained in kinetic Monte Carlo simulations. The emission and absorption coefficients to be used in cluster dynamics are fully defined: they depend not only on the free energy of clusters but also on the whole cluster distribution. Alternatively, this model can provide accurate values of the nucleation driving force used in classical nucleation theory.