The location of the transition points for the three main Harrison's kinetic regimes (types A, B and C) for the measurement of grain boundary diffusivities from tracer concentration depth profiles (self-diffusion) had been extensively studied by making use of the phenomenological Lattice Monte Carlo numerical method. Those locations were mainly dependent upon the dimensionality of the problem. For the case of impurity grain boundary diffusion, the segregation effect was very important. In the present study, the influence of segregation on the transition points was investigated for the parallel slab model (2-dimensional) of the grain boundary diffusion problem by making use of the tracer-type solution to the equivalent diffusion problem. It was shown that the type-B regime was most likely not realized for the cases of fine-grain material with a strong segregation effect present.

The Harrison Diffusion Kinetics Regimes in Grain Boundary Diffusion: Lattice Monte Carlo Modeling of the Effect of Segregation. I.V.Belova, G.E.Murch, T.Fiedler: Defect and Diffusion Forum, 2011, 309-310, 9-18