Aluminum Foil Wool Recrystallization And Precipitation Behavior

The recrystallization and precipitation behavior in AA1235 aluminum alloy sheets was investigated by XRD, TEM, optical microscopy, hardness, and tensile test. The solid solubility of Fe and Si alloy was analyzed by the lattice constant method, and with which the TTP(Time-Temperature-Precipitation) curves in the temperature range from 325℃to 400℃were obtained.1. Lattice constant method was used to quantify the Fe, Si in AA1235 aluminum alloy. The Fe and Si content dropped as the annealing was prolongated; The pre-deformation stimulates the precipitation behavior. As a result, low content Fe,Si can be achieved by those samples with high pre-deformation reduction under the same annealing conditions.2. The nose temperature of aAlFeSi is 375℃from the TTP curves for AA1235 aluminum alloy. Pre-deformation plays more important role in stimulating precipitation for DC(Direct casting) sheets than that for TRC(Twin Roll Casting) sheets. The former has larger precipitation rate as the pre-deformation is 90%, while the later can get this advantage as the pre-deformation changes to 50%.3. Grain sizes were in the range of 37-44μm when the sample was annealed at 375℃/1h with about 70% reduction, and the grains didn't grow up as the annealing continued. The precipitation and recrystallization coexisted during annealing. The precipitates, with sizes between 0.5μm and 2μm, were mostly found around the grain boundaries and dislocation areas.4. High pre-deformation reduction can stimulate the precipitation behavior, the higher pre-deformation reduction, the higher the elongation for the samples under the same annealing conditions. The properties of the sheets were promoted most effectively when annealing under the nose temperature. In this paper, the samples with 90% pre-deformation, annealed at 375℃/1h, had the best performance during the tensile.