Mg-RE-TM合金强化相中的点缺陷及其对力学性能的影响

项目名称： Mg-RE-TM合金强化相中的点缺陷及其对力学性能的影响

项目编号： No.51461002

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 唐壁玉

作者单位： 广西大学

项目金额： 48万元

中文摘要： 镁合金被誉为新型绿色工程材料。本课题运用密度泛函理论研究Mg-RE-TM合金强化相中点缺陷的原子尺度微结构特征和形成能，建立结构模型，揭示形成机制和微观过程，进而运用化学势探索点缺陷形成能、结构和分布组分环境改变。完善和建立浓度-温度及浓度-组成曲线，深化理解不同温度下点缺陷的浓度和分布以及强化相的化学组成配比，从而发展和完善相图组成。通过点缺陷掺杂体系形成焓，确立点缺陷结构和分布对掺杂位置倾向选择性和热力学过程的影响，揭示点缺陷结构与掺杂过程、微合金化机制和微结构之间重要的密切关联，优化微合金化过程和性能。运用点缺陷体系中广义层错能量曲面，揭示点缺陷与层错位错的相互作用，以及点缺陷结构浓度对材料形变微观过程和强韧性的关键性影响和机制。进一步研究点缺陷体系弹性性能等揭示强度、硬度、延展性，揭示其力学性能。为优化控制Mg-RE-TM合金的形成、结构和性能并促进其应用提供依据和指导。

中文关键词： 镁合金；力学性能；合金化

英文摘要： Mg alloy is praised as a new type of green engineering materials. Using density functional theory, this project would study the atomic scale microstructure of point defects in strengthening phases of Mg-RE-TM alloys and the formation energy of these point defects, so as to construct the corresponding structural models and reveal formation mechanism and microscopic process. Based on the function of formation energy of point defects, the environment dependence of formation, structure and distribution of the point defects would be further investigated. Especially the relation curves of concentration versus temperature and component concentration would be established and improved to deepen the understanding of temperature dependence of concentration and distribution of point defects, and to construct and improve phase diagrams. From the formation enthalpy of doping process in defect system, influence of defect structure and distribution on position preference of dopants and doping thermodynamics would be uncovered, important and close relationship of defect structure with doping process, micro-alloying mechanism and microstructure would be established, and micro-alloying and its performance would be optimized. By calculation of generalized stacking fault energy surface, interaction of point defect with stacking faults and dislocations would be revealed, and influence of defect structure on deformation micro-process and property of strength and toughness, along with the underlying mechanism, would be deeply understood. Furthermore, elastic property of point defect system would be studied to reveal the feature of mechanical property such as strength, stiffness, brittleness and ductility. This program would provide evidence and instruction for optimization and design of formation, structure and property of Mg-RE-TM alloys, so as to promote the application of Mg alloys.

英文关键词： Mg alloy;mechanical property;alloying