The cyclic diffusional charging/discharging of a plane sheet specimen was analyzed theoretically for the unique case where chemical diffusion propagated moving phase boundaries. This cyclic variation of the classical Stefan moving-boundary problem introduced additional complexities which were associated with the interaction and annihilation of phase boundaries. By using a finite difference method, with local mesh adaptations to allow for the moving phase boundary, the dynamic steady-state condition was investigated as a function of cycle duration and shape, for various equilibrium concentrations at the phase boundaries. Two main classes of steady-state behavior were observed. These involved either complete phase transformations on each cycle (type-C steady-state) or incomplete transformations where the specimen remained mainly in one phase and transformed only partially during each cycle (type-I steady-state).

Dynamic Steady-State during Cyclic Diffusional Phase Transformations. C.A.Schuh: Journal of Applied Physics, 2002, 91[11], 9083-90