A thermodynamic analysis was made of isothermal phase equilibria and diffusion in coherent planar multi-layers. The formal aspects of diffusion in binary and ternary solids were reviewed, and the expected effects of coherency strain upon diffusional homogenization were outlined. It was noted that the diffusion formalism could often be extended, so as to account for coherency strains, simply by substituting the coherent free-energy density for its incoherent counterpart. In ternary and higher-order systems, it was always possible to choose an initial condition that was free from strain. It was not generally possible to maintain this strain-free condition during diffusional homogenization. The general effect of strain energy upon ternary diffusion was to rotate the diffusion eigen-vectors so that the strain was reduced.

G.R.Purdy, Y.J.M.Brechet: Acta Materialia, 1996, 44[12], 4853-64