5083 aluminum alloy sheet with excellent mechanical properties fabricated by constrained ring groove pressing based on a cyclic stress state

Abstract

A new process of repeated compression and deformation by warm and circular waves based on a cyclic stress state is proposed. This process prepares 5083 aluminum alloy plates with greatly improved mechanical properties. Results show that the overall thickness of the sheet is relatively uniform after ring wave deformation. As the flattening temperature increases, the uniformity of the sheet thickness improves. First, the grain refinement effect is the best after four passes of deformation when the flattening temperature is 200 °C, and the average grain size is refined from 24 μm to 8.0 μm. As such, the hardness of the obtained sheet is the largest, and the Vickers hardness increases from 82.3 HV to 101.6 HV. Second, the mechanical properties of the sheet after three passes of deformation are better when the flattening temperature is 250 °C. The tensile strength and the fracture elongation greatly improve. The tensile strength is 295 MPa, which is 10.7 % stronger than the original sheet. Fracture elongation is 28.76 %, which corresponds to a 56.3 % increase compared with that of the original sheet. Third, when the flattening temperature is 300 °C, the comprehensive mechanical properties of the sheet after three passes of deformation are the best. The tensile strength of the sheet is 289.6 MPa, which is 8.6 % higher than that of the original sheet, and the maximum elongation at break is 32.2 %, which is 75.0 % higher than that of the original sheet. The SEM morphology of the room-temperature tensile fracture of the sheet with different deformation conditions shows that the number of micropores and dimples in the room-temperature tensile fracture, the maximum size, and the number of white tear edges increase as the flattening temperature increases. Consequently, sheet toughness and plasticity improve.