Importance of Disclinations in Severe Plastically Deformed Materials

Abstract A short overview of recent achievements in disclination approach application to severe plastically deformed materials is given. Necessary definitions and designations: Volterra rotational and translational dislocations, disclination Frank (rotation) vector, wedge and twist disclinations, are introduced and explained. The properties of screened disclination configurations (loops, dipoles, defects in small particles etc.) with relatively small energies are considered. Disclination models for the processes in the structure of plastically deformed materials are reviewed. The bands with misorientated crystal lattice in metals and other materials are described as a result of partial wedge disclination dipole motion. The disclination approach is applied to the description of workhardening at large strains and to the analysis of grain boundaries and their junctions in conventional polycrystals and nanocrystals.