Recrystallization behavior of rolled ingots of 6061 and 6069 aluminum alloys

The purpose of this study was to investigate the recrystallization characteristics of rolled, as-cast, annealed, and homogenized ingots of “Air-Slip”™ Direct Chill (ASDC) 6061 and 6069 aluminum alloys. The % R_x for annealed and homogenized 6061 and 6069 ingots is higher than that of as-cast 6061 and 6069 ingots at a given % CW and heat-treatment temperature. There is no significant difference in % R_x between annealed ingots and homogenized ingots of the same composition at a given % CW and heat-treatment temperature. The % R_x for 6069-AC ingot is higher than that of 6061-AC ingot at a given % CW and heat-treatment temperature, especially at low heat-treatment temperatures. The % R_x of annealed 6069 ingot (6069-A) and homogenized 6069 ingot (6069-H) is slightly higher than that of corresponding 6061 ingots at a given fraction % CW and heat-treatment temperature. The difference in the recrystallization behavior may be related to the increased alloy additions, in excess of the solubility, leading to relatively large second-phase particles, particularly MgSi₂. This can lead to particle-stimulated recrystallization.