Effect of accumulative roll bonding (ARB) and subsequent aging on microstructure and mechanical properties of 2024 Al alloy

Abstract

In this study, bulk nanostructured 2024 Al alloy sheets with optimized strength and ductility were successfully prepared through an effective thermo-mechanical process including solution treatment, heavy deformation by accumulative roll bonding (ARB) and cold rolling (CR), and subsequent low temperature aging. A lamellar boundary structure with mean grain thickness of 40 nm could be clearly observed after 3-cycle ARB and 50% CR with total equivalent strain of 3.2. The ultimate tensile strength and elongation to failure of the ARB+CR processed sample were 599 MPa and 1.7%, respectively. After subsequent low temperature aging at 100°C for 20 h, the ultimate tensile strength and elongation to failure became 635 MPa and 7%, respectively, showing simultaneously increased strength and ductility compared to the cold-worked state. The reasons for the superior mechanical properties were discussed.