Stress and Strain Effect on Defect Structure Parameters of Single Crystals in Cu–12 at.% Al Alloy

The paper presents a thorough analysis of the dislocation structure of the Cu-12 at.% Al alloy single crystals with [001] deformation axis at room temperature. It is shown that the multiple stages of strain hardening are associated with different types of the dislocation substructure appearing during the deformation process. The dislocation network is observed at all deformation stages and has specific properties at each stage. Measured are the parameters of the dislocation network and its evolution is studied. The dependences are obtained for the dislocation density, strain and shear stress. The linear dependence of τ(ρ1/2) is true prior to strain at the beginning of stage III. It is found that the transition to stage III is caused by twinning, which drastically reduces the dislocation density.