Recrystallization in Multilayer Al99.99/AlMg3 Laminates Prepared by Accumulative Roll-Bonding

Composite multilayer sheets from Al/AlMg3 with 32 alternating layers of Al and AlMg3 were prepared by accumulative roll-bonding and their thermal stability was studied. Recrystallized 2 mm thick sheets of a commercial twin-roll cast AlMg3 alloy and high purity Al99.99 served as input materials. Electrical resistivity measurements were used for the integral monitoring of solute atoms distribution during annealing. Light optical microscopy was employed for the direct grain-size determination and recrystallization description. Post-mortem electron microscopy observations were performed on as-prepared and annealed specimens and they were combined with in situ heating electron microscopy in order to explain the observed annealing effects. A broadening of Al layers during annealing was observed and related to diffusion of magnesium.