Changes in Microstructures during Annealing after Cold-Rolling at 30% and 50% Reduction on Al-Mg-Si Alloy

Recrystallization phenomena in an Al-Mg-Si alloy cold-rolled at 30 and 50% reduction rates were observed on the same area in specimens during annealing at 673 K using SEM-EBSD method. After recovery in a narrow sense occurred, coarse subgrain microstructures were formed by migrating high angle boundaries at both reduction rates. The coarse subgrain microstructure contained low angle boundaries, and orientation gradients were observed in contrast to the recrystallized microstructure. Lattice rotation due to cold-rolling was recovered in the coarse subgrain microstructures for the case of 30% reduction. When the specimen was cold-rolled at 50%, lattice rotation occurred over a broad range of angles. As a result, prior grain boundaries became unclear, and the majority of the subgrains were surrounded by high angle boundaries. Some of the subgrains showed the coarse subgrain microstructure, and the others grew into recrystallized grains. [doi:10.2320/matertrans.L-MZ201122]