Recrystallization in Al‐Mg Alloys after Hot Compression

Because the 5000-series aluminum alloys are not heat treatable, controlling their microstructures during deformation processing to achieve fine grain sizes is particularly important. Recrystallization during or immediately following hot deformation provides an opportunity for controlling grain size prior to cold deformation. The present study investigates the effects of magnesium concentration, temperature, and deformation rate on re-crystallization during and immediately after hot upsetting. Three aluminum alloys with magnesium concentrations of 0.0, 0.5, and 4.5 wt.% were upset at 400 and 500 °C at fixed strain rates of 0.1, 1.0, and 10.0 s−1. The specimens were rapidly quenched after upsetting to preserve their microstructures. Portions of the specimens were then annealed for 10 min. to allow static recrystallization. Cross-polarized optical microscopy was used to examine the as quenched and annealed specimens. These results are interpreted to explain microstructural evolution during and after hot deformation.