Shear banding phenomenon in a Cu-8 at.% Al alloy analysed by orientation imaging microscopy

The microstructure and texture of Cu-8 at.% Al alloy single crystal with (112)[11 1] orientation plane strain compressed at 77 K were characterized by scanning electron microscope and transmission electron microscope orientation mappings in order to investigate the influence of twins and shear bands on slip propagation across a structure of twin-matrix layers and the resulting texture evolution. It was shown that the strong, initial texture changes are due to deformation twinning at low deformations. At larger deformations, twin-matrix bending within some narrow areas led to the formation of kink-type bands, which became the precursors of shear bands. It is shown with scanning electron microscope and transmission electron microscope orientation mappings how the structure of twins and matrix was incorporated into the shear band, and what kind of the dislocation mechanism was responsible for strain accommodation at the macroscale. It was found that the reorientation of the main (111) twinning planes towards the shear band plane facilitates further dislocation slip in the shear direction.