The influence of Zener drag on recrystallization behaviour of twin-roll cast AA8079 alloy after homogenization

Abstract

Intermediate annealing is a crucial step of aluminum foil production. The as-cast material hardens during rolling and an annealing step is required at intermediate gauges to soften the material and restore its ductility.

Generally, fine recrystallized structure could assure sufficient ductility for further rolling and processing. Recrystallization of the material during intermediate annealing can be controlled by a microstructure tailored during homogenization.

Recrystallization behaviour of a twin-roll cast aluminum alloy AA8079 was studied. The as-cast strip was homogenized at 420 °C and 580 °C and rolled down to two different thicknesses.

Evolution of microstructure of rolled materials during a model intermediate annealing was studied, and Zener drag and particle stimulated nucleation were determined as mechanisms controlling recrystallization.