Effect of Temperature and Velocity of Pressing on Grain Refinement in AA5083 Aluminum Alloy During Repetitive Corrugation and Straightening Process

Repetitive corrugation and straightening experiments were carried out on sheets of aluminum alloy, AA5083, at room temperature and 573 K (300 °C) and two pressing velocities (0.5 and 2 mm/s). In every case, the sheet was processed to the maximum possible number of passes. Electron backscattered diffraction analysis and transmission electron microscopy were used to characterize microstructure evolution. After room temperature processing with a pressing velocity of 0.5 mm/s, the average grain size had decreased to ~11 microns from ~45 microns, with 70 pct of the grain boundaries of the high-angle type. In contrast, sub-grain formation was present at a pressing velocity of 2 mm/s. Mechanical properties like tensile strength and hardness were correlated with microstructures. It is concluded that the velocity of pressing plays a crucial role in grain refinement and recovery and the resulting mechanical properties, as the time available for dislocation rearrangements during processing depends strongly on this variable. An increase in temperature of deformation leads to softening and a deterioration in the mechanical properties.