Annealing Characteristics of an Al-6.5Mg-1.5Zn Alloy Cold-Rolled After Casting

The annealing characteristics of a cold rolled Al-6.5Mg-1.5Zn alloy newly designed as an automobile material is investigated in detail. The aluminum alloy in the ingot state is cut to a thickness of 4 mm, a total width of 30 mm and a length of 100 mm and then reduced to a thickness of 1 mm (reduction of 75%) by multi-pass rolling at room temperature. Annealing after rolling is performed at temperatures ranging from 200 to 400 degrees C for 1 hour. The tensile strength of the annealed material tends to decrease with the annealing temperature and shows a maximum tensile strength of 482MPa in the material annealed at 200 degrees C. The tensile elongation of the annealed material increases with the annealing temperature, while the tensile strength does not, and reaches a maximum value of 26 % at the 350 degrees C annealed material. For the microstructure, recovery and recrystallization actively occur as the annealing temperature increases. The recrystallization begins to occur at 300 degrees C and is completed at 350 degrees C, which results in the formation of a fine grained structure. After the rolling, the rolling texture of {112}< 111 >(Cu-Orientation) develops, but after the annealing a specific texture does not develop.