Recent experiments on diffusion at migrating grain boundaries, occurring during discontinuous reactions. were summarized. Such reactions included discontinuous precipitation and diffusion-induced grain boundary migration. Analytical electron microscopy was used to measure solute concentration across individual solute-depleted α-lamellae. These data were combined with information, on the growth velocity and the thickness of an individual lamella, in order to determine local values of the diffusivities of the moving reaction front of discontinuous precipitation cells in Al–Zn, Ni–Sn, Cu–In and Co–Al alloys. The resultant diffusivities and activation energies were very similar to the equivalent parameters for stationary grain boundaries. It was concluded that there was no significant difference in the rates of diffusion along migrating and stationary grain boundaries in these systems. It was proposed that diffusivity values for the moving reaction front of the discontinuous precipitation reaction could be a source of information on interfacial diffusion characteristics. This was especially true of systems and/or temperatures where radiotracer data were not available.

Diffusion Along Migrating Grain Boundaries. P.Zieba: Interface Science, 2003, 11[1], 51-8