Texture evolution and flow stress of columnar-grained polycrystalline copper during intense plastic deformation process at room temperature

Abstract

The texture evolution and microstructure in continuous columnar-grained (CCG) polycrystalline copper during wire drawing at room temperature were investigated quantitatively using the electron backscatter diffraction (EBSD) technique, and the stored energy and flow stress were calculated based on the texture constitution and structural parameters of different texture components measured by high resolution EBSD. The results indicate that the development of 〈1 1 1〉 texture within original 〈1 0 0〉 columnar grains was significantly slower compared with that in equiaxed polycrystalline copper, e.g. the volumetric ratio of the 〈1 1 1〉 to 〈1 0 0〉 component in columnar-grain copper was 0.82 at the strain of 2.98, while it was 2.96 in equiaxed polycrystalline copper at the same strain. The relatively low content of 〈1 1 1〉 fiber texture accounted for the low flow stress, low work hardening rate and excellent cold plastic extensibility of the columnar-grained polycrystalline copper. The average size of the dislocation cells developed within the 〈1 1 1〉 fiber was the minimum among all the deformation texture components, and decreased rapidly with the increase of strain, leading to a high stored energy, a high flow stress and a high work hardening rate. On the other hand, the average size of the dislocation cells developed within the 〈1 0 0〉 fiber was the maximum, which held a large value at high strain, leading to a low stored energy, a low flow stress and a low work hardening rate.