Patterns of the localization of plastic deformation in Hadfield steel single crystals under tension

Abstract

The patterns of plastic flow localization in high-manganese γ-Fe FCC single crystals undergoing the twinning while stretched are obtained by the experimental procedure of double-exposure laser speckle photography, which permits accurate in situ measurement of plastic distortion tensor components during specimen loading and analysis of local strain distributions over the tested specimen. Basic spatiotemporal features of strain localization at the stages of yield plateau, easy glide, and linear hardening are established. The type of ordered space-time arrangement of localization nuclei, i.e. the type of localized deformation wave, which is observed for the respective flow stage (yield plateau, easy glide, linear and parabolic work hardening), is determined by the acting law of work hardening. The velocity of strain localization sites moving upon stretching is determined. Conditions under which plasticity autowaves appear in the strained medium are discussed. It is demonstrated that the local strain distributions in the case of twinning are similar to those due to dislocation glide.