Grain Boundaries in Severely Deformed Materials: Structure, Properties, and Thermal Evolution

The presentation is focused on structure-property relationship for interfaces in severe plastically deformed (SPD) materials. The results are systematized for different types of SPD treatment, imposed strain, and induced defects, and the deformation parameters used (temperature, total strain and strain rate). The kinetic properties of interfaces in a broad spectrum of severe plastically deformed materials ranging pure metals to alloys, including the high-entropy alloys, are measured. A multi-level hierarchy of short-circuit diffusion paths is shown to be formed in ultrafine grained materials produced by SPD Treatment [1,2]. The key properties of deformation-modified grain boundaries, such as interface width, diffusion rate, free volume excess, are measured and analyzed in detail. A model of the deformation-modified grain boundary state is presented.