Classification of the solute concentration profiles in the discontinuous solid state phase transformations

A classification of the solute concentration profiles in the discontinuous solid state phase transformations is presented based on the results published in the literature during the last twenty years. Two types of the profiles are distinguished: Profiles (i) parallel and (ii) perpendicular to the reaction front. Most of the results relevant for discontinuous precipitation, coarsening and dissolution were obtained using analytical electron microscopy. The classification for diffusion-induced grain boundary migration was extended by presenting a third type of the profiles: a depth profile. This is because most of the information obtained for that reaction comes from the application of the standard electron probe microanalyser, which is rather three-dimensional in comparison to the analytical electron microscopy used for the determination of the other profiles.