Recrystallized microstructural evolution of UFG copper prepared by asymmetrical accumulative rolling-bonding process

Copper sheet with grain size of 30-60 μm was processed by plastic deformation of asymmetrical accumulative rolling-bonding (AARB) with the strain of 3.2. The effects of annealing temperature and time on microstructural evolution were studied by means of electron backscattered diffraction (EBSD). EBSD grain mapping, recrystallization pole figure and grain boundary misorientation angle distribution graph were constructed, and the characteristics were assessed by microstructure, grain size, grain boundary misorientation and texture. The results show that ultra fine grains (UFG) are obtained after annealing at 250 °C for 30-40 min. When the annealing is controlled at 250 °C for 40 min, the recrystallization is finished, a large number of small grains appear and most grain boundaries consist of low-angle boundaries. The character of texture is rolling texture after the recrystallization treatment, but the strength of the texture is faint. While second recrystallization happens, {110}〈12〉+{112}〈11〉 texture component disappears and turns into {122}〈212〉 cube twin texture component.