固溶合金元素对镁基体热变形滑移的影响机理

准确掌握镁合金不同温度下的滑移变形机理，是调控镁合金成形性能、开发新型高性能镁合金的关键基础。然而，由于镁合金基体相中元素长程无序的固溶特点，以及有限温度下(>0K)复杂的热、电子、晶格振动相互作用，基于第一性原理方法准确计算镁合金固溶体有限温度下(>0K)的本征属性一直是一个科学难题。本项目拟以相干势近似等新型固溶合金理论及热力学统计分布方法为基础，建立有效描述复杂固溶状态下镁合金有限温度(>0K)性能的第一性原理计算预测方法；实现镁合金广义层错能等本征属性及其温度演化规律的准确计算；明晰不同温度下固溶合金元素影响镁合金滑移变形机理的内在本质。结合先进微观表征手段，探究镁合金成分、本征塑性参数、滑移变形机制及性能间的量化对应关系。为基于电子结构计算的高性能镁合金研发奠定科学基础。

Understanding of slip deformation mechanisms at various temperatures is crucial to tailor the formability of magnesium alloys and design new magnesium alloys with advanced properties. However, it remains a big challenge to quantitatively describe intrinsic properties of magnetism alloys at finite temperature (>0K) in solid solution state by using first-principle calculations, owing to the chemical long-range disorder in magnesium bulk phase, and complex interactions between temperature, electrons and lattice vibration at thermal state. In the project, a first-principle based predictive method will be established to describe the intrinsic properties of magnesium alloys at finite temperature (>0K), on the basis of the solid solution theory such as the coherent potential approximation and the thermal statistical methods; The accurate description of the intrinsic properties including the generalized stacking fault energies and also their temperature dependence will be achieved; The rationale behind the influence of alloying elements in solid solution state on the slip deformation mechanisms of magnesium alloys at finite temperature will been clarified. In combination with the advanced experimental characterizations, the correlation between the chemical composition, intrinsic plastic parameters, slip deformation mechanisms, and mechanical properties of magnesium alloys will be elucidated. The findings are expected to underlay the foundation for the development of magnesium alloys with advanced properties on the basis of the electronic structure calculations.