The Manning relations for atomic diffusion in a binary ordered alloy

In this paper we explore the validity of the technologically important Manning relations which connect the phenomenological coefficients to the tracer diffusion coefficients in alloys. Derived originally for the random alloy, here the Manning relations are shown analytically to be equally valid for an isotropic binary ordered alloy model where the two sublattices have equal numbers of sites and where only intersublattice jumps are possible; an example is the B2 structure. Ordered structures where intrasublattice jumps occur will require rather extensive additional consideration.