铝合金具有密度小，比强度高，耐蚀性能好、易回收等优点，成为汽车轻量化的首选材料。但由于铝合金室温成形性能差，易发生开裂现象，制约了铝合金在汽车工业中的广泛应用。本项目将等径角轧制工艺应用到6系汽车铝合金板材成形过程，探讨汽车车身铝板等径角轧制成形机理及形/性一体化成形工艺。项目以晶体塑性理论为基础，构建6016铝合金的晶体塑性本构方程和等径角轧制的3D晶体有限元模型，结合实验分析铝合金初始织构、轧制工艺、热处理等对板材组织与性能的影响。在汽车铝板成形性能分析的晶体有限元模型中引入扩展有限元，避免模拟过程中微裂纹萌生的网格细化和微裂纹扩展的网格重新划分的问题，同时结合成形极限实验，从宏、细、微观三个尺度揭示汽车铝合金中晶粒大小、第二相粒子、织构以及晶粒层次不均匀变形对铝板成形性能的影响规律。在此基础上，优化汽车铝合金等径角轧制、热处理工艺，为高性能汽车铝合金板材成形提供理论依据和技术支持。

Aluminum alloys have become the first choice material of automobile lightweight because of their excellent properties such as low density, high strength to weight ratio, good corrosion resistance and low cost recycling. However, it is easy to cause the phenomena of fracture due to its poor formability at room temperature, which often acts as the main obstacle for the wide application of aluminum alloys to automotive industry. The equal channel angular rolling is applied to the formation of 6xxx auto aluminum alloy sheets, and the mechanism of equal channel angular rolling of auto body aluminum sheet and its formation/performance integrated forming processes are discussed. Based on the crystal plasticity theory, the crystal plasticity constitutive equations of 6016 aluminum alloy and 3D crystal plasticity finite element model of equal channel angular rolling are created, and the effects of initial texture, roll parameters and heat treatments on the microstructure and properties of aluminum sheets are discussed by experimental observations and FEM simulations. To avoid mesh refinement in microcrack initiation and remesh in microcrack growth, the extended finite element method is introduced in the FEM simulation on the formability of auto aluminum sheets. Integrating the experiments of forming limit, the law of the effects of grain size, particle,texture and grain scale inhomogeneous deformation on the formability of aluminum sheets is analyzed at the macro-scale, meso-scale and micro-scale. Based on the above study, the equal channel angular rolling, heat treatments are to be optimizated to offer the basic theory and technical support for the formation of high performance auto aluminum sheets.