Diffusion along a bi-material interface was complicated by the fact that different species were evolving under the influence of the same thermodynamic driving forces but at different rates. If the phases were assumed to be rigid this leads to the problem being over-determined. Relaxing this constraint so that the phases could deform elastically removes this problem. Diffusive creep deformation of a number of 2-phase elastic systems with idealised geometries were analysed using differential and variational methods. If the connectivity of the phases was such that one phase cannot deform without the deformation of the other then the deformation rate was determined by the least mobile component. However, if this was not the case, such as for a distribution of precipitates within a polycrystalline matrix, it was principally the mobility of the matrix phase that determines the deformation rate.

Interfacial Diffusion in a Two-Phase Material Accommodated by Elastic Relaxation. S.P.A.Gill: Acta Materialia, 2005, 53[13], 3737-49