Decomposition of the supersaturated solid solutions at the stage of coalescence under conditions of passage from dislocation-controlled to volume diffusion

Abstract

The object of a theoretical examination is here the heterogeneous isomorphic continuous decomposition of supersaturated solid solutions for the case of binary aging alloys with a developed dislocation structure under enhanced temperatures in the unsteady stage of coalescence, whose transient nature is caused by the instability with respect to a change in the mechanism of mass transfer acting in the system, which controls coarsening of the disperse heterophase structure. For the quasi-stationary diffusion regime, a complete analytical description of the evolution of the second-phase-size distribution function is given for the stage of the transient kinetics, when the initially prevailing diffusion along dislocations, which supply the alloying component to the precipitation phase, is succeeded by volume diffusion at the last stages of decomposition.