非对称热挤压变形镁合金织构与塑性调控及织构形成机制研究

项目名称： 非对称热挤压变形镁合金织构与塑性调控及织构形成机制研究

项目编号： No.51271046

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 王轶农

作者单位： 大连理工大学

项目金额： 80万元

中文摘要： 变形镁合金作为一种新型轻质金属结构材料在现代制造业具有广阔的应用前景。采用传统热变形技术制备的变形镁合金通常会产生强烈的{0001}基面织构，该基面织构的存在是导致镁合金室温塑性低的重要原因之一。针对这一关键问题，本项目提出了非对称热挤压技术制备高塑性变形镁合金板材这一新的方法，即通过热挤压模具孔型的非对称设计，旨在热挤压变形过程中引入较大的切应力，使得镁合金在动态再结晶晶粒细化的同时弱化基面织构。利用细晶强韧化和织构韧化的双重耦合作用，提高镁合金的室温塑性。通过对比研究镁合金在对称和非对称热挤压变形过程中的动态再结晶行为、织构特征及其影响因素，着重揭示基面织构的形成与弱化机制，建立动态再结晶微观组织与取向（织构）形成相关联的物理模型，明确微观组织特征参量与综合力学性能（拉伸性能和成型性能）之间的关联系，丰富和发展镁合金动态再结晶理论，为制备高塑性变形镁合金提供理论与实验基础。

中文关键词： 变形镁合金；非对称热变形；动态再结晶；基面织构；力学性能

英文摘要： Wrought magnesium alloys are emerging as potentially good candidates for numerous applications, especially in transportation vehicles and lightweight enclosures for modern industrial products owing to their good properties, such as low density and high specific strength. However, the disadvantage of wrought magnesium alloys is that they generally exhibit limited ductility due to their hcp crystalline structure and strong basal texture at room temperature. Therefore, it is required to improve their poor ductility at room temperature. In the view of industrial practice, the thermo-mechanical treatment (TMT), such as hot extrusion and hot rolling is one of efficient forming technology to refine grain size and change crystalline textures, which are the key prerequisites for the microstructural capable of deformation. The main aim of the current project will be emphasized on the dynamic recrystallization (DRX) behavior and textural development of wrought magnesium alloy sheets fabracated by asymmetric hot extrusion process, which is expected to be result in a fine-grained microstructure and a weak basal texture. The evolution and formation mechanism of non-basal texture induced by asymmetric hot extrusion will be investigated by the measurements of macro and micro texture and analysis of microstructure. The physical

英文关键词： wrought alloy；asymmetric deformation；dynamic recrystallization；basal texture；machanical properties