A Study of Diffusion-Induced Grain Boundary Migration (DIGM) in Ni-Sn and Ni-In Alloys

On the basis of light and scanning electron microscopy observations, diffusion induced grain boundary migration (DIGM) has been observed to occur in Ni-8 at.% Sn and Ni-7.5 at.% In alloys heated in atmospheres low in Sn and In, respectively. For these alloys boundary migration results from the diffusion of Sn and In out of the alloys along the grain boundaries and the formation of dealloyed zones behind the boundaries. It has also been observed to occur in pure Ni when the Ni is heated in an atmosphere containing Sn and In. In this case boundary migration results from the diffusion of Sn and In into the pure Ni along grain boundaries and the formation of alloyed zones behind them. In addition, diffusion-induced recrystallization (DIR), was also found to occur in both the Ni-In and Ni-Sn binary systems after extended times at 850C and 900C during both mixing and unmixing