Influence of deformation mechanisms on grain refinement

The chapter deals with a cause of essential differences in the estimates of accumulated strain at different SPD techniques and far smaller grains refined to a minimum size. A new approach to determine a value and distribution of shear and rotational components of accumulated strain affecting grain refinement and grain boundary misorientations is analyzed. A relationship is established between key parameters of deformed and structural states on the basis of fundamental principles of mechanics and physics of plastic deformation. The following equations are obtained: kinetics of shear deformation development and structure fragmentation, accumulation of charge and tensor densities of dislocations, dependence of grain sizes and misorientations of their boundaries on accumulated strain degree, and scale factor of a metal sample.