A phenomenological model for multi-component diffusion in B2 body-centered cubic ordered phases was applied to the present system. The activation energy for diffusion was expressed as a function of the degree of ordering, as deduced from thermodynamic data. These data were also used to deduce the thermodynamic factors for diffusion. It was shown that the model was capable of representing the experimental data. The diffusivities which arose from the model were used to simulate 6 different diffusion experiments. The results were compared with experimental data, and it was concluded that the model yielded satisfactory predictions.

Diffusion in the B2-BCC Phase of the Al-Fe-Ni System - Application of a Phenomenological Model. T.Helander, J.Agren: Acta Materialia, 1999, 47[11], 3291-300