Dynamic steady state during cyclic diffusional phase transformations

TitleDynamic steady state during cyclic diffusional phase transformations
Publication TypeJournal Article
Year of Publication2002
AuthorsSchuh, CA
JournalJournal of Applied Physics
Pagination9083 - 9090
Date Published2002/06/01/

The problem of cyclic diffusional charging/discharging of a plane sheet specimen is analyzed theoretically, for the unique case where chemical diffusion propagates moving phase boundaries. This cyclic variation of the classical Stefan moving boundary problem introduces additional complexities associated with the interaction and annihilation of phase boundaries. Using a finite difference method with local mesh adaptations to allow for the moving phase boundaries, the dynamic steady state condition has been investigated as a function of the cycle duration and shape, and with various equilibrium concentrations at the phase boundaries. Two main classes of steady state behavior are observed, involving either complete phase transformations on each cycle (type-C steady state) or incomplete transformations where the specimen remains primarily in one phase, only partially transforming on each cycle (type-I steady state). Maps of the steady state character have been developed for various conditions, and the results of many simulations are synthesized into guidelines for prediction of the steady state. (C) 2002 American Institute of Physics.