Thermomechanical Treatment of High-Shear Melt-Conditioned Twin-Roll Cast Strip of Recycled AA5754 Alloy

Abstract

A continuous high-shear melt conditioning twin-roll casting process has been developed for production of recycled aluminum alloy strip with minimum casting defects. High-shear melt conditioning is applied to increase the impurities tolerance of recycled aluminum. The results of this study showed that solidification during twin-roll casting can be controlled by using intensive melt conditioning prior to casting, which can promote equiaxed growth with minimal defects and result in improved sheet quality. Melt-conditioned twin-roll cast (MC-TRC) AA5754 alloy exhibited fine equiaxed grains and homogenized matrix structure while centerline segregation was eliminated. As-cast melt-conditioned twin-roll cast AA5754 strips showed clear grain recrystallization after thermomechanical treatment at 430°C for 30 min, representing an improvement over conventional twin-roll casting. The MC-TRC strip showed 57.2% higher elongation and 4.1% higher ultimate tensile strength compared with the TRC strip after applying melt conditioning with thermomechanical treatment.