Study On Microstructures And Mechanical Properties Of 2A23 Aluminum Alloy By Age Forming Process

Stress age forming process for 2A23 aluminum alloy plate has been investigated systematically. Springback regular under the different processes conditions is studied, by measuring radius of the plates. And in the same way, the effect of surface plastic strain on the springback is studied through the different radiuses of tools. Microstructure evolution during the ageing process and through thickness position is researched using optical microscope (OP), scanning electron microscope (SEM), transmission electron microscope (TEM) and electronic back-scattered diffraction (EBSD) technique. Based on the experiment results, the influence of stress on microstructures is discussed. The effect of age forming on properties is studied by measuring the hardness and electrical conductivity under the ageing processes.The springback analyses of age forming for 2A23 aluminum alloy plates show that, as expected, increasing ageing time reduces the amount of the springback. At the early stage of age forming, the springback value is up to 54%. The effect of surface plastic strain on the springback is notable. But in the whole, 2A23 aluminum alloy has good age-formability.Microstructure analyses show that the main strengthen precipitate of 2A23 Al alloy plate is S' phase, which has precipitated in the form of laths with {210}Al habit planes. Compared to stress free aged alloy, the size of S' and S phase of the ageformed alloy plate increases. S' phase precipitates fully at the surface plastic strain zone. It is due to stress and plastic strain.The tensile test results show that compared to stress free aged alloy, at the under ageing stress aged alloy has higher yield strength but opposite at the over ageing. However the tensile strength and elongation decreases. The yield strength of the thicker ageformed plate is higher than the stress free ageing through the thickness position. And the improvement of the yield strength decreases from the surface to the mid-thickness. Plastic strain and stress gradient make the improvement of the yield strength different in the thickness dicretion.The electrical conductivity results show that the electrical conductivity of the age-formed 2A23 Al alloy plate is higher than stress free ageing alloy at the different ageing time. The plastic strain and stress makes the electrical conductivity of the surface low.