Microstructural response of copper foil to a novel double-cross rolling process

Bending resistance is regarded as a significant factor in achieving the widespread application of copper foils. This paper proposed a novel double-cross rolling process, which improved the bending fatigue life of copper foils by as much as 101% in comparation with conventional rolling. In this study, an investigation was conducted into the effects of double-cross rolling on the microstructure and texture of copper foils and the strengthening mechanism during the bending test was discussed. Results show that double-cross rolling could change the deformation behavior on bright and matt surfaces, resulting in equiaxed grains on both surfaces and some fine grains. Both surfaces were dominated by Brass and S textures, which can be attributable to from non-uniform and shear deformation respectively. Weak Goss and Cube textures resulted from the fine grains remaining after heat treatment. After double-cross rolling, the strain induced subgrains of copper foils facilitated the migration of grain boundary and grain rotation, thus improving bending property.