Fabrication of high-strength and high-ductility laminated A2024 aluminum alloy/aluminum composite by severe plastic deformation under high pressure

In this study, the method of high-pressure torsion (HPT) was applied for grain refinement of A2024/Al composites. Diffusion bonding was carried out at 773 K for 5 h to form the composite in advance. Disk samples with 10 mm diameter and 1 mm thickness were processed by HPT under a pressure of 6 GPa. The chemical composition of the diffusion treated Al layer was determined to Al-2.5%Cu-1.3%Mg by EDS analysis. Microstructural observations revealed that the grain size was refined to -180 nm in the thickness center and -440 nm in the surface side. Tensile tests showed that the ultimate tensile strength reached 710 MPa with a total elongation of 9%. Extra strengthening was attained by aging at 423 K after HPT processing, leading to an ultimate tensile strength of 760 MPa at the peak-aged condition.