Microstructural changes in presence of externally applied potential gradients

Materials in service rarely experience the uniform isothermal conditions used in the laboratory to characterize the microstructural stabilities of alloys. Heterogeneities in some environmental parameters (such as temperature, stress, or electric fields) can cause potential energy gradients within the material, and these provide a driving force for diffusion that can lead to microstructural instabilities in polyphase alloys. This paper explores the conditions under which such effects may dominate over those normally observed that derive from reductions in the internal energies of alloys.