Plastic behaviour of copper sheets during sequential tension tests

摘要: Abstract Sequences of two uniaxial tension tests along different axes were performed on a polycrystalline copper sheet. In order to reach better understanding the physical mechanisms occurring during second deformation, effect strain path change subsequent yield and flow behaviour has been investigated using optical transmission electron microscopy. The value reloading stress is function angle φ between tensile axes. For >15° requirement glide dislocations with new Burgers vector implies that very low density potentially mobile available at beginning deformation. This moderated values about 90° by inverse activity some slip systems reloading. transient observed in work-hardening after concomitant disappearance dislocation walls developed prestrain. A more homogeneous substructure appears for > 15° as result interactions active previous walls; dissolution arrangement also promoted inversion direction systems, depending φ. results an increase dynamic recovery rate early stage reloading, particularly when approaches 90°.