随镁合金应用的增加，与镁合金构件在服役条件下的阻尼性能和疲劳性能等密切相关的镁合金微塑变研究逐渐引起了研究者的关注。本项目将首先以商业纯镁为主，采用单向拉伸试验和循环单向加卸载试验研究晶粒度和织构对纯镁微塑变的影响规律，然后研究合金化和第二相对镁合金微塑变行为的影响。通过透射电子显微镜研究不同微小塑性变形量下显微组织、原位TEM观察微塑变加载卸载下的动态组织演变规律，辅以同步辐射原位加载获得的晶格应变演化。将循环加卸载的应力-应变测试与微观组织结构的观察结合起来，系统深入地研究镁合金微塑性变形的变形规律及显微组织结构演变，揭示微塑变机理。研究结果将加深对镁合金阻尼行为和疲劳行为的理解，为高阻尼镁合金、尺寸稳定性镁合金、耐疲劳镁合金的研究开发提供理论指导。

With the increasing application of Mg alloys, the microplastic deformation of Mg alloys has drawn the attention of researchers, because the microplastic deformation is closely connected with the damping behavior, fatigue and other properties of materials. The first step of the project is to investigate the effect of grain size and texture on the microplastic deformation behavior of pure Mg, then the effect of alloying and second phases on the microplastic deformation behavior of Mg alloys is studied. The microstructure of the Mg and its alloys after loaded at different microstrains will be observed by transmission election microscope (TEM), and an in situ transmission electron microscopy study will be performed on the Mg and Mg alloys during cyclic loading and unloading in the microyield regime. In addition, the lattice dependant strain development in the elastic as well as in the plastic region during the cyclic loading and unloading of the Mg and Mg alloys in the microyield regime will be investigated. The microplastic deformation behavior and microstructure evolution will be studied systematically through careful analysis of the relation between cyclic loading-unloading and microstructural evolution, in order to shed light on the mechanism of microplastic deformation of Mg and Mg alloys. The project will promote further understanding of the damping behavior and fatigue of magnesium alloys, and provide theoretical guidance for developing high performance magnesium alloys with high damping capacity, high dimensional stability and high fatigue resistance.