Theory of diffusional phase transformations in nanocrystalline alloys upon severe plastic deformation: III. Alloys with limited solubility

In the frameworks of the model of regular solid solutions taking into account the different diffusion mobility of the components, the effect of fluxes of nonequilibrium vacancies on the kinetics of decomposition of the alloy is studied. It is shown that the joint action of thermodynamic stimuli of decomposition and the inverse Kirkendall effect gives rise to the precipitation of phases near sources and sinks for vacancies even if the alloy parameters fall into the region of mutual solubility of the components. It has been established that under specific conditions the effect of vacancy fluxes can lead to the formation of special space-time structures (traveling concentration waves). Features of the alloy decomposition upon severe plastic deformation, when grain boundaries serve as sources of nonequilibrium vacancies, are discussed. Copyright © 2005 by Pleiades Publishing, Inc