2A66铝锂合金往复墩-挤大塑性变形微观结构演变规律及强韧化机制研究

项目名称： 2A66铝锂合金往复墩-挤大塑性变形微观结构演变规律及强韧化机制研究

项目编号： No.51474101

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 高文理

作者单位： 湖南大学

项目金额： 82万元

中文摘要： 铝锂合金具有高比强度、高比刚度、高弹性模量和良好的可焊性，是航空航天领域最具应用潜力的结构材料。但铝锂合金单向挤压机械纤维(流线)和晶体学纤维呈明显各向异性，晶粒沿挤压方向被拉长，形成纤维组织，使晶界的杂质、第二相粒子的形貌与分布呈带状限制了铝锂合金的应用。项目采用往复镦-挤技术对2A66铝锂合金进行大塑性变形，通过对试样连续的镦粗和挤压塑性变形，获得等轴的细晶组织，消除铝锂合金单向挤压机械纤维组织，改善晶界杂质、第二相粒子的形貌与分布的均匀性，解决2A66铝锂合组织的各向异性问题，提高其耐损伤及抗疲劳性能。项目主要研究2A66铝锂合金往复镦-挤的变形机制、组织结构演变规律及其对力学性能的影响，揭示铝锂合金往复镦-挤变形的强化韧化机制，为利用往复镦-挤变形技术改善铝锂合金形变组织的均匀性，细化晶粒，进一步提高其强韧性指标，制备高强高韧铝锂合金型材奠定理论基础。

中文关键词： 铝合金；组织演变；力学性能；大塑性变形；变形机制

英文摘要： Al-Li alloy is a kind of potential material for application in the field of aerospace, owing to its high specific strength and stiffness, high elastic modulus, good fatigue resistance and weldability. However, the alloy exhibits the fibrous structure, such as elongated grains, the impurity particles and second phase distributed along the direction of the metal plastic flowing during the normal deformation, which is an important issue in its application. In the present project, 2A66 Al-Li alloy were deformed by a modified repeated upsetting and extrusion (RUE) process for the purpose of refining grains, weakening fibrous structure, improveing distributed uniformity and morphology of the impurity particles and second phase, abating of anisotropy, enhancing damage resistance limit and fatigue strength of 2A66 Al-Li alloy. The deformation mechanisms, the evolution law of the microstructure and tensile properties during multi-pass RUE process was studied; moreover, the strengthening and toughening mechanism of RUE processed 2A66 Al-Li alloy was explored. The purpose of this investigation lies in providing a theoretical guidance for the industrial preparation of high-performance 2A66 Al-Li alloy with fined-grain microstructure, uniform second phases and impurity particles distribution.

英文关键词： Al Alloy;Microstructure Evolution;Mechanical Property;SPD;Deformation Behavior