Analysis of Geometrical and Structural Factors Determining Plastic Flow of Twins in Zinc Crystals

摘要

The analysis of the geometry of twinning in zinc, the influence of the initial orientation of crystals (from the lines: [0001]-[1120] and [0001]-[1010] of the standard triangle) on the value of Schmid factor for twinning systems and the geometrical and structural conditions for basal slip activity in twinned areas are presented. It has been found that: i) only in the case of (tensiled) crystals with orientation close to [1120] twinning leads to the increase of the Schmid factor for the basal system, and such mode of slip can be theoretically accompanied by the effect of 'geometrical softening'; ii) the 'latent hardening' of twins, resulting from the twinning transformation of the matrix dislocation structure, suppresses (or at least make difficult) the basal slip at low temperatures, and at higher ones - it stimulates the recrystallization process; iii) the effect of 'geometrical softening' of twins would be realized at medium temperatures only, when the processes of structure regeneration are controlled by 'dynamic recovery'.