镁锂合金是目前最轻的金属结构材料，在航空航天以及兵器工业等领域备受关注。双相Mg-Li合金具有较好的综合力学性能，是目前的研究热点。双相Mg-Li合金中，由于两相强度与塑性差异，易导致塑性变形不协调，但是目前关于双相Mg-Li合金变形机制研究较少，与其有关的多个关键科学问题尚需系统研究。本申请以离心铸造制备的具有梯度组织特征的双相Mg-Li合金为研究对象，综合利用多种先进的微观结构分析手段、准原位拉伸试验方法和数值模拟技术，系统研究具有梯度组织特征的双相Mg-Li合金变形过程中的组织遗传行为、变形协调行为和梯度组织对合金的力学性能的影响规律，揭示其组织遗传机制，探明其变形协调机制，揭示梯度组织对合金宏观力学性能的影响规律。通过本项目研究，可丰富和发展超轻双相Mg-Li系合金的协调变形理论，为合金的组织调控、塑性变形和性能优化提供重要的理论指导。

Mg-Li alloys, as the lightest known metallic structural materials, have been attracted more and more attentions in the fields of aerospace, spaceflight and weapon industry, etc. Duplex Mg-Li alloys possessing good comprehensive mechanical properties, are the research focus at present. In duplex Mg-Li alloys, the difference of strength and ductility between the two phases tends to lead to inharmonic plastic deformation. However there are few reports on the plastic deformation mechanism of duplex Mg-Li alloys at present and several important scientific problems need a systematical investigation. Thus, the microstructure heredity behavior, deformation coordination behavior and the influence of gradient microstructure on the macro-mechanical properties of duplex Mg-Li alloys with gradient microstructure prepared by centrifugal casting are systematically investigated combing the usage of many advanced microstructure characterization methods, quasi in-situ tensile test and numerical simulation method. The aim of this project involves disclosing the microstructure heredity mechanism, finding out the deformation coordination mechanism and revealing the influence of the gradient microstructure on the mechanical properties of Mg-Li alloys. The results from this project contributes to the development of deformation theory for superlight duplex Mg-Li alloys, which can be used to tailor microstructure, deformation and mechanical properties of Mg-Li alloys.