Evaluation of diffusion data in the type AB transition regime

Abstract

In the literature, characterization of new diffusion regimes can be found that can better describe measured diffusion profiles in fine-grained advanced materials. In this connection, the possibility to evaluate the measured data also in the transition-type kinetics gathers importance. Recently, some diffusion experiments were published introducing nanostructured materials in the transition regime between the Harrison's types A and B. In this regime (called type AB kinetics), the penetration profiles correspond to the relation ln c ¯ ∼ y n . Here, the exponent n varies from 2 to 6/5 as the diffusion regime changes from types A to B. This paper presents an easy approximate method for estimation of the grain boundary (GB) diffusion characteristics from sectioning measurements in the type AB transition kinetics.