Microstructure and texture evolution of cold drawing 〈110〉 single crystal copper

Abstract

By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation 〈110〉 parallel to axial direction have been investigated in the present work. In order to analyze the effect of initial orientation on microstructure and texture of drawn copper, the results of the drawn 〈100〉 single crystal copper wires have been compared with 〈110〉 and 〈111〉 single crystal copper wires. It is found that the grain subdivision of 〈110〉 single crystal is more evident than that of 〈100〉 and 〈111〉, and the textures consisting of 〈111〉 and 〈100〉 abruptly form in the drawn 〈110〉 single crystal. At high strains, due to shear strain, the distribution of fiber textures is imhomogenous along the radial direction of drawn 〈110〉 single crystal copper wires. 〈100〉 is near the surface and 〈111〉 is at the center. The microstructure results of drawn 〈110〉 single crystal show that at low strains, it can be characterized as two kinds of geometrically necessary boundaries with noncrystalline character. At medium strains, S bands can be observed. At high strains, lamellar boundaries form. Mean misorientation and average spacing of dislocation boundary are larger in drawn 〈110〉 single crystal, as compared with 〈111〉 and 〈100〉. In drawn 〈110〉 single crystal with high strains, the bimodal distribution forms at lower strains than in drawn 〈100〉 single crystal, which is because the dislocation boundaries with high angle are contributed by not only the boundary between 〈111〉 and 〈100〉 fiber textures but also the boundary in 〈111〉 or 〈100〉 texture.