The self-diffusion of Fe was investigated by using the radiotracer technique and 59Fe. Most of the measurements were performed in the B2-structure regions of the phase diagram, plus some in the A2-structure region and a few in the D03-structure region. There were 2 ordering transitions; between A2 and B2, and between B2 and D03. Both of them led to an increase in the activation enthalpy for diffusion in the phase having the higher degree of order. The data could be described by:

Fe74.5Al25.5 (A2):     D (cm2/s) = 8.1 x 10-1 exp[-2.26(eV)/kT]

Fe74.5Al25.5 (B2):     D (cm2/s) = 3.8 x 100 exp[-2.40(eV)/kT]

Fe74.5Al25.5 (D03):     D (cm2/s) = 3.3 x 101 exp[-2.88(eV)/kT]

M.Eggersmann, H.Mehrer: Philosophical Magazine A, 2000, 80[5], 1219-44