ABSTRACT
Different plastic deformation processes (tensile loading, compression, rolling, extrusion, creep, fracture) are usually characterised by distinctive stages. Of these stages of active deformation, uniaxial tension and compression have been studied most extensively. This chapter analyses the current views regarding the individual stages of plastic deformation and work hardening of the polycrystals. The stages of deformation of the polycrystalline metallic materials were generalised for the first time in the well-known monographs. The chapter describes the eight-stage pattern of plastic flow of the metallic polycrystals that has been experimentally determined. It includes the critical analysis and generalisations of the patterns of work hardening of both meso- and sub-micropolycrystals. It reviews the current views on the individual stages of work hardening. Attention is given to the role of structural transformations in the formation of the individual stages of plastic deformation. The chapter describes the changes in the deformation mechanisms, leading to the occurrence of new hardening stages.
