Evolution of the Microstructure of Steel in the Processes of Severe Plastic Deformation

The development of new materials and technologies using various methods of intense energy impacts has brought to the fore the problems of studying the physics of plastic deformation under these conditions. The methods listed in this review include the large or severe plastic deformations, which cause the reduction in grain sizes to the nanoscale level, significant increase in the density of various types defects, deformation phase transformations, and other changes in microstructure, providing new opportunities for modifying not only mechanical, but also fundamental physical properties of materials. In this case, firstly, nonequilibrium structural states including heterophase ones and (or) with a high density of defects and stored deformation energy are formed. Secondly, in these states new mechanisms of plastic flow different from traditional (dislocation) ones appear. Activation of such mechanisms determines the need for their comprehensive study at various from nano- to macrostructural levels, identifying the physical patterns of the formation and evolution of the above-mentioned nonequilibrium structural states, new mechanisms and carriers of plastic deformation.