THE ELASTIC STABILIZATION OF MULTIPLE-HEIGHT GROWTH LEDGES DURING DIFFUSIONAL PHASE-TRANSFORMATIONS

In diffusional phase transformations that proceed by the terrace-ledge-kink mechanism, both atomic-scale, unit-height ledges and multiple-height ledges are observed. Both types of ledges also have dislocation character, thereby making them disconnections. The dislocation interaction is shown to provide a strong stabilizing force for the multiple ledges and to lead to a capture distance for additional unit ledges that increases with ledge height. Implications for the mechanism of phase transformation are discussed.