We carried out calculations of the thermodynamic factor Phi entering the Da
rken equation for interdiffusion. Phi is expressed in terms of the energy p
arameters which describe the ordering process in the binary alloy. Our calc
ulations for Fe-Al alloys show the dependence of Phi on the long-range orde
r parameter. These calculations are performed with the parameters extracted
from the diffuse X-ray scattering data on FeAl. We emphasize the influence
of the concentration dependence of energy parameters on Phi, for different
temperatures in our calculations. (C) 1998 Elsevier Science S.A. All right
s reserved.