Role of dislocations and generation of twins during diffusion induced grain boundary migration

Abstract

Although the reduction in the free energy of mixing due to alloying (or de-alloying) is generally accepted as the driving force for diffusion induced grain boundary migration (DIGM), the mechanisms so far proposed give only a limited explanation of how the process is induced, particularly the initial stages. This work further examines the role of solute via the development of compressive stresses at grain boundary segments. It is suggested that the reduction in the vacancy chemical potential of the stressed boundary is the primary driving force leading to DIGM through gliding and/or climbing of grain boundary dislocations.

MST/1403