Changes in Recrystallized Texture after Annealing of 5083 Aluminum Alloy Cold Rolled at Increasing Reduction Rate

Abstract

The recrystallized textures of 5083 aluminum alloy plates were examined. These plates were cold rolled at total reduction rates of 30, 50 and 85%, followed by annealing. When reduction rate was 30%, recrystallization was not complete and recovered grains remained despite annealing the specimen at 673 K for 10.8 ks in a salt bath. Recrystallized grains were mostly formed through particle stimulated nucleation, while strain induced grain boundary migration was scarcely occurred. The orientations of recrystallized grains were similar to those of the grains obtained after cold rolling. The orientations of recovered grains were returned to those of the grains before cold rolling with annealing. When reduction rate was 50%, the lattice rotations in the grains increased slightly as compared with the specimen that was cold rolled at a reduction rate of 30%. The distribution of the orientation was close to that of a β–fiber composed of copper, brass and S orientations. Several grains with the {142} plane parallel to the rolling direction were observed. On the contrary, the grains with the {111} plane parallel to the rolling direction decreased. When reduction rate was 85%, the image of the microstructure formed after cold rolling could not be obtained using SEM–EBSD. This was because Kikuchi patterns were not clear owing to the formation of dislocation tangles close to the rolling surface. EBSD images could be obtained by annealing the specimen at 673 K for 3 s. It can be considered that dislocation tangles were rearranged and changed into subgrains. The orientations of recrystallized grains close to precipitations were considerably irregular. However, these grains were difficult to grow. The grains with the {142} plane parallel to the rolling direction were more in the specimen cold rolled at a reduction rate of 85% than in the specimen cold rolled at a reduction rate of 50%. It was concluded that the <142>//ND texture was gradually constructed by increasing the total reduction rate for the cold rolling of 5083 aluminum alloy. [doi:10.2320/jinstmet.J2017001]