Gradient energy, interfacial energy and interface width

The gradient energy coefficient, χ, and interface width, δ, are estimated from data on concentration profiles across interfaces between two phases in coherent contact. Using the sigmoid function to describe the concentration profile, χ and δ are evaluated knowing only the interfacial energy and the concentrations of the phases on both sides of the interface. Coherent interfaces in Ni-base and Al–Ag alloys are examined. The values of χ and δ obtained favorably compare with those reported in the literature.