塑性成形变加载模式对镁合金微观组织和成形性能影响研究

The plastic forming of magnesium alloys has become a focus in the field of material forming. The forming equipment and forming process based on controllable dynamic technology are the newest trend in the forming processing field. Microstructure and formability of magnesium alloy during the plastic forming procedure under the conditions of multi-physical field at the changing load model based on controllable dynamic equipment will be studied..Firstly, AZ31 magnesium alloy is selected as the studying object and the generation mechanism of dynamic recrystallization and static recrystallization will be studied according to the analysis on microstructure and deformation behavior of magnesium alloy during the plastic forming procedure under the changing load model. And the influence of dynamic recrystallization and static recrystallization on microstructure and deformation behavior will be explored..Secondly, the deformation mechanism and fracture mechanism will be researched according to study the deformation behavior and the microsopic such as dislocation, twinning and fracture surface, et al in order to explore the mechanism of enhanced formability. .Lastly, the design criterion and develop method of plastic forming for magnesium alloy under the conditions of multi-physical field at the changing load model will be established based on the numerical simulation of the deforming and the microstructure and the experiment..The plastic forming theory and technology of magnesium alloy will be enriched and the new forming process for servo forging equipments will be developed. The achievements not only have an important scientific significance and a theoretical value, but also have a wide application value and a huge market prospect.

镁合金塑性成形是材料成形领域研究的热点之一；动力可控的塑性成形设备及其成形工艺研究是成形加工领域的最新发展趋势。本项目提出基于动力可控的变加载模式多物理场耦合作用下镁合金塑性成形技术。.首先，以AZ31镁合金为对象，通过对塑性成形过程中微观组织演化和变形行为分析，探讨变加载模式下动态与静态再结晶发生的机理，研究其对微观组织和变形行为的影响；其次，通过对位错、孪晶、断口等微观分析和变形行为宏观研究，分析其变形机理与断裂机制，探讨变加载模式改善镁合金塑性成形性能的途径和机理；最后，在宏观变形与微观组织数值模拟基础上并结合实验研究，建立变加载模式多物理场耦合作用下镁合金塑性成形工艺设计准则和制定方法。.通过本项目研究，不仅能够丰富镁合金塑性成形理论和技术，还可开发基于伺服锻压设备的塑性成形新工艺，不但具有重要的科学意义和理论价值，还具有广阔的应用价值和巨大的市场前景。

镁合金塑性成形理论与新工艺研究是材料成形领域研究的热点之一；伺服成形装备及其成形工艺研发是成形加工领域的最新发展趋势。本项目对提出的基于动力可控的变加载模式多物理场耦合作用下镁合金塑性成形理论与技术进行了系统、深入的研究。.项目以半连续铸造AZ31镁合金为对象，对变加载模式下镁合金在对塑性成形过程中微观组织的演化和变形行为进行了分析，探讨了变加载模式下镁合金动态与静态再结晶发生的机理，与匀速驱动模式相比，采用伺服变速驱动模式可是材料组织更加均匀、晶粒更加细小，且随着变速模式的不同其细化效果也不同；同时，与匀速模式相比，伺服变速模式晶粒取向一致性较弱，这与伺服变速变形时孪生发生有一定关系。对伺服驱动模式下镁合金塑性成形工艺分析与实验研究表明，采用伺服成形工艺，可有效提高镁合金成形性能，与匀速驱动模式相比，其可锻性可提高20%以上。.通过本项目研究，不仅丰富了镁合金塑性成形理论和技术，还开发了基于伺服锻压设备的塑性成形新工艺，具有重要的科学意义和理论价值，已推广应用到铝合金精锻成形等工艺上，具有广阔的应用价值和巨大的市场前景。