About the Formation of the Supersaturated Solid Solutions by Diffusion Process
It is generally agreed that during diffusion process between two phases e.g. matrix/diffusant layer the thermodynamic equilibrium state is fulfilled and the supersaturated solid solutions can not formed by diffusion. Nevertheless, in many cases the formation of equilibrium phases does not occur due to kinetic and other reasons, and metastable phases can be formed. The analysis of the concentration profiles for bulk diffusion obtained at low temperatures consistent with B-regime for grain boundary diffusion in systems Cu/Al, Fe and Co/Cu is performed. It is shown that in these systems the supersaturated solutions are formed and the extent of supersaturation is the more as the diffusion temperature is lower. The concentration of diffusant may be 5-10-times greater than solubility according to phase diagram.
S.V. Divinski, H. Bracht and N.A. Stolwijk
A. O. Rodin et al., "About the Formation of the Supersaturated Solid Solutions by Diffusion Process", Defect and Diffusion Forum, Vol. 363, pp. 35-39, 2015