Diffusion mobilities for the B2-b.c.c. phase in the Ni–Al binary system

A model for diffusion is applied to the Ni–Al system to optimize the mobility parameters for the B2-b.c.c. phase by fitting the experimentally obtained diffusivities. In the model, the activation energy for diffusion is expressed as a function of the degree of ordering which is evaluated from thermodynamic data. The diffusivities from the model are used to simulate diffusion experiments. The results are compared with experimental data and it is concluded that the model can yield satisfactory prediction.