Study on superplastic gas-bulging properties and microstructure evolution of as-rolled 2A97 Al-Li alloy

Abstract. In this paper, the forming properties of as-rolled 2A97 Al-Li alloy at 370 ~430 ℃ and 0.02~0.08 MPa/min were studied by Superplastic gas-bulging experiment, the microstructure and mechanical properties of 2A97 Al-Li alloy after deformation were evaluated and analysed by means of EBSD, TEM and other testing methods. The results show that the as-rolled 2A97 Al-Li alloy has good superplastic deformation ability, the optimum forming parameters are 390℃, 0.06 MPa/min, and the maximum height of cap cone is 74 mm under these conditions. Dynamic recry -stallization of rolled microstructure occurs during superplastic deformation, the microstructure after superplastic deformation is fine, equiaxed and the average grain size is less than 5 μm. The material keeps good strength and plasticity after superplastic deformation, the tensile fracture shows obvious ductile fracture characteristics, and there are a lot of dimples with regular shape and uniform distribution on the fracture surface. After superplastic forming, it undergoes 520 ℃/2h solution treatment, water quenching, and aging at 165 ℃/36h, the properties of 2A97 Al- Li were as follows: tensile strength 527MPa, yield strength 441MPa, and elongation 8.3%, respectively.