基于多因素影响的AZ31镁合金轧制残余应力研究

In this study a commercially AZ31 magnesium alloy hot rolled plate with a strong basal texture will be chosen as the starting material, wedge-shaped plate samples with different initial textures will be rolled by single pass at different temperatures; The microstructure and texture evolution during rolling will be quantitatively characterized using electron backscatter diffraction (EBSD) and macro-, micro-residual stress will be measured by the newly developed short wavelength X-ray internal stress analyzer; The effect on macro-, micro residual stress by initial texture, rolling temperature and reduction will be systematically investigated; slip, twinning and dynamic recrystallization mechanism during rolling will be studied and its effect on rolling microstructure and residual stress distribution homogeneity will be discussed in detail; ultimately, the relationship among rolling deformation mechanism and dynamic recrystallization-rolling microstructure and residual stress distribution-rolling capability and property of final plate will be built and it will provide theoretical foundation to develop new rolling technology for magnesium alloy and improve mechanical properties of magnesium alloy plates.

本课题拟选择具有强烈基面织构的商用AZ31（Mg-3%Al-1%Zn）镁合金热轧板材，设计具有不同初始取向的楔形板样品，在不同温度下进行单道次轧制；利用EBSD技术对轧制过程微观组织及织构进行定量表征，采用最新研制的短波长X射线体应力仪对轧制过程板材内部残余应力进行测定，系统研究初始取向、温度及变形量对轧制板材内部宏观及微观残余应力及其分布的影响，深入分析镁合金滑移、孪生变形机制及动态再结晶行为对轧制变形组织均匀性、残余应力分布均匀性所产生的作用，建立轧制变形条件所导致的轧制变形机制与动态再结晶行为-轧制组织结构及残余应力分布状态-轧制成形能力及板材性能三者之间的相互关系,为开发镁合金新型轧制工艺及改善镁合金板材力学性能提供理论指导。

本课题创新性的设计了镁合金不同初始织构楔形板单道次轧制实验来研究轧制条件对镁合金轧制变形能力和变形机制的影响。在前期研究基础之上，揭示了柱面滑移大量启动对镁合金轧制变形能力提升的重要作用。阐明镁合金轧制温度、变形能力，变形机制之间的相互关系，为开发镁合金新型轧制工艺及改善镁合金板材力学性能提供理论指导。另成功开发短波长X射线无损分析技术，已用于部分晶体结构材料内部结构分析。