动态再结晶（DRX）是金属热成形中的重要物理现象与变形机制，而多晶体塑性模拟是理解变形物理过程和揭示变形机理的有效方法。项目针对镁合金热变形研究中动态再结晶模型无法反映复杂变形路径和织构演化、晶体塑性模型不能计算再结晶过程的问题，以AZ31、Mg-Al和Mg-Y镁合金为对象，从宏微观结合的角度，基于晶体塑性理论与动态再结晶过程分析，研究DRX晶粒形核与长大、小角度晶界向大角度晶界转变等微观特征的建模与计算方法，在多晶体均匀化理论构架下，建立多晶体塑性-非连续动态再结晶和多晶体塑性-连续动态再结晶集成自洽计算模型；构建热挤压成形仿真模型，实现应力应变、晶粒细化与织构演变的耦合模拟；分析不同DRX机制之间的转换关系，揭示初始微观组织、变形条件等因素对DRX的影响规律，探索镁合金DRX织构的形成机理及其与DRX过程之间的相互关系。通过本项目研究，促进镁合金塑性变形理论和晶体塑性计算方法的发展。

Dynamic recrystallization (DRX) is an important physical phenomenon as well as deformation mechanism during hot forming processes of metals. Crystalline plasticity based simulation of plastic deformation is an effective method for understanding physical essence and clarifying internal mechanism of deformation. The present DRX modelling methods cannot account for complex deformation path and texture evolution, while crystaline plasticity simulation cannot compute DRX process. In this project, taking AZ31, Mg-Al and Mg-Y alloys as study objects , the integrated computation method of crystalline plasticity and DRX will be established. Based on crystalline plasticity theory and DRX mechanism characterization, the modelling methods for crystal slip, twinning, DRX grain nucleation and growing, transition from low angle boundaries to high angle boundaries, etc. will be researched. The integrated models for polycrystal plasticity-discontinuous DRX and polycrystal plasticity-continuous DRX will be established respectively. The established model will be applied to simulation of magnesium alloy extrusion processes, and the evolution of stress-strain, grain size and texture will be simulated in a coupled way. Furthermore, the relationship between different DRX mechanisms, the influence of initial microstructure and deformation conditions on DRX, the formation mechanism of DRX texture and its impact on DRX will be explored. This research work will contribute to the development of crystalline plasticity computational methodology and plastic deformation theory of magnesium alloys.