Distribution of the Composition across the Interface in Binary Alloys

For one-dimensional case of binary substitution alloys, the parameters of the diffuse interface and the distribution of the composition within it are calculated using the thermodynamic approach. It is shown that the estimate of the equilibrium solubility limits in the quasi-regular solution model coincides with the results of the Gibbs construction and the results obtained using the Cahn–Hilliard approach. It is found that the interface width weakly depends on the chosen approximation. A strong dependence on the employed approximation is characteristic of the equilibrium solubility limits. It is also demonstrated that approaches that are different from the quasi-regular solution model lead to a violation of Maxwell’s equal area rule. It is shown that the parameters determining the shape of the distribution curve of the composition along the interface have substantially different behavior within the quasi-regular solution model and in the case of regular calculations.