采用OM、SEM、EMPA、DSC、电导率和常温拉伸性能测试等手段，分别对传统双辊铸轧及电磁双辊铸轧2种工艺条件下制备的2099Al-Li合金的微观组织及性能进行了深入研究，分析了双辊铸轧过程中的偏析产生机理及电磁振荡场的作用机制。结果表明：双辊铸轧工艺将连续铸造和轧制变形结合为一道工序，解决了传统铸造方法制备Al-Li合金因Li元素的加入而导致的严重缩孔等问题，但在铸轧板材中心存在宽度接近1 mm的宏观偏析带。在铸轧过程中施加电磁振荡场后，偏析带基本消除；二次枝晶臂间距缩减至6.90 μm；Cu、Zn、Mg元素的偏析度分别降低至2.45、0.93、1.05；合金中的非平衡共晶相含量显著降低。相较于双辊铸轧工艺，电磁双辊铸轧制备的2099Al-Li合金板材的抗拉强度、屈服强度、延伸率分别提升了34 MPa、18 MPa、2.8%，合金的力学性能得到大幅改善。

Al-Li alloy has been widely applied in the fields of aircraft, aerospace and military applications due to its superior comprehensive properties. Al-Li alloy prepared by traditional casting process will have shrinkage porosities and gas holes defects due to the gas absorption of lithium element. Twin-roll casting (TRC) process combines continuous casting and rolling deformation into one process. The melt subjected to a certain rolling force during cooling and solidifying, compensates for the solidification shrinkage of liquid metal in the roll-casting region, hence solving the problems of porosity and other defects in Al-Li alloy. However, due to the wide solidification range of 2099Al-Li alloy, the central macro-segregation inevitably occurs in the sheets produced by TRC, which seriously deteriorates the mechanical properties of the sheets. How to eliminate segregation in aluminum alloys strips by adjusting the rolling parameters has been studied for decades. But the effect was not obvious and new approaches are required to solve this challenge. Introducing electromagnetic oscillation field in TRC process may be an effective way to solve the central segregation in TRC sheets. In this work, the OM, SEM, EMPA, DSC, conductivity and tensile test are employed to study the microstructure and properties of 2099Al-Li alloy prepared by TRC and electromagnetic TRC, respectively. The Lorentz force generated in the roll-casting region by applying electromagnetic oscillation field during TRC, which can break the dendrite and refine the solidification structure of the alloy. The central segregation band of the TRC sheet basically eliminated, and the segregation degree of Cu, Zn and Mg elements reduced to 2.45, 0.93 and 1.05. The macro-segregation and micro-segregation of sheets were effectively reduced. At the same time, the electromagnetic oscillation field can enhance the mixing ability of solute atoms, reduce the content of non-equilibrium eutectic phase and improve the supersaturated solid solubility of matrix. Compared with TRC sheet, the tensile strength, yield strength and elongation of 2099Al-Li alloy sheet prepared by ETRC increased by 34 MPa, 18 MPa and 2.8% respectively, hence the mechanical properties of the alloy sheet were greatly improved. This research work provides a new idea for the efficient preparation of Al-Li alloy with energy-saving, high-efficiency and green environmental protection.