Lateral Growth in Solid-Solid Phase Transformations

The problem of step motion during lateral growth in solid-solid phase transformations is considered. The present model is concerned with the case in which volume diffusion in the parent phase is the predominant contribution to the growth rate, and it is assumed that the steps do not interact appreciably. The relationships between growth rate and supersaturation are obtained from an approximate solution of the diffusion equation in a moving coordinate system. The predictions of the model are then tested against the observed behavior of steps in Al-15 wt.% Ag as reported by Laird and Aaronson, and good agreement is found.