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Mg-Li alloy called ultra-light magnesium alloy is the lightest metal structure material has a higher specific strength than rigidity, good plasticity, and excellent electromagnetic shielding performance advantages in the aerospace and weapons industry, automobiles, electronics and other fields has good prospects for development. With the energy crisis and people's awareness of environmental protection, the lightweight, recyclable materials demand more urgent, Mg-Li alloy applications will also be more and more widely. In this thesis, the rare earth elements Gd, Ce and ultrasound field, the electromagnetic field of the Mg-Li alloy solidification organization and its performance and use of the PIV physical simulation technology to simulate the flow field of ultrasonic field and obtained the following results: Mg- 8Li-3Al alloy consists of α and β two phase composition of Mg-8Li-3Al alloy microstructure can effectively change the cover, add the rare earth elements of Gd and elements Ce. Add elements Gd, white precipitate phase, the organization is refined and relatively rounded at the phase boundary; the add elements Ce, in the beta phase and the phase boundary precipitates Al2Ce, refined alloy microstructure. PIV simulation results show that the structure of the ultrasonic downstream field ultrasonic action, the flow field to exist around two loop-like structure close to the the ultrasound tool head front-end position, the flow field with greater speed. With the increase in the power of ultrasonic vibration, the flow velocity of the flow field, the effect is more obvious in the front of the tool head position, velocity increases. Mg-8Li-3Al alloy melt at different temperatures applied ultrasound field. The study showed that the slightly higher temperature above the liquidus applied ultrasonic field can significantly improve the alloy solidification structure, this description of the pressure - too cold mechanism may be the major ultrasound refinement mechanism. The ultrasound tool head front position to the most granular solidification structure, with the increase of the distance from the ultrasonic tool head, the ultrasonic energy is attenuated the effect smaller solidification structure refinement weakened. Power ultrasonic vibration is applied to the Mg-8Li-3Al alloy. The results showed that the ultrasonic power 170W, can significantly improve the Mg-8Li-3Al alloy microstructure α phase morphology from rose-like structure into a small nearly spherical structure and refinement with the prolongation of the ultrasonic time effects are getting better and better. 170W ultrasound treatment 90s after the alloy samples, the corrosion resistance and mechanical properties have significantly improved tensile strength and elongation 184MPa and 18.5%, respectively, compared to the sample without sonicated improve 9.5% and 45.7%, respectively. Preliminary study on the impact of electromagnetic fields on Mg-9Li-5Al-Zn alloy, the results show that the electromagnetic field is applied, the solidification structure, α-phase morphology by a long strip structure into a nearly spherical structure, mechanical properties of the alloy is significantly improved.
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