The kinetics of the discontinuous ordering reaction were studied in a polycrystal of Fe-50at%Co alloy, in which the orientations of individual grains were determined by means of orientation imaging microscopy. Most of the grain boundaries which exhibited a low reaction-rate could be characterized as being special coincidence site lattice boundaries with a low value of the inverse density of coincident sites. The inactivity of the special grain boundaries was attributed to the low value of the self-diffusion coefficient. It was demonstrated that the low-S grain boundaries exhibited a low diffusivity, regardless of their inclination and tilt or twist nature.

Evidence for Slow Self-Diffusion along Special CSL Grain Boundaries from the Kinetics of Discontinuous Ordering in Fe-50at%Co. E.Rabkin, V.Semenov, E.Bischoff, W.Gust: Materials Science Forum, 1999, 294-296, 601-4