高强铝合金拼焊车身构件热冲压成形技术基础研究

This program combines the national fundamental requirement of automotive. Aiming at the engineering forming problems of the complex surface thin-walled aluminum alloy body parts, such as materials difficult to weld, construction difficult to form and the accuracy and performance of the part difficult to control, the research on hot stamping of high strength aluminum alloy friction stir welding (FSW) body parts is carried out. Based on the theoretical analysis, numerical simulation and technological experiment, the heterogeneous structure and the evolution of aluminum alloy FSW welding body parts are studied during hot stamping. The mechanism of the heterogeneity of the structural characteristics on formability of FSW body parts is revealed under the thermo-mechanical coupling non-uniform deformation effect. Then thermo-mechanical coupling control method on the whole process of microstructure stabilization and strengthening is established. The transfer mechanism of geometric accuracy for the aluminum alloy FSW body parts is studied during hot stamping with multi-zone non-uniform deformation. The mechanism of the multi-zone non-uniform deformation characteristics on geometrical accuracy of the FSW body parts is revealed during hot stamping. The constraints and coordination mechanism of dies on geometric accuracy during multistep forming process of aluminum alloy FSW body parts is exhibited. The prediction and control theory of microstructure and geometrical accuracy of aluminum alloy FSW body parts under non-uniform deformation during hot stamping are established, which provide engineering scientific basis for the forming of aluminum alloy FSW body parts. The research can promote the technological application and development of the automotive lightweight in China.

本项目结合汽车轻量化国家重大需求，针对复杂曲面薄壁铝合金拼焊车身构件材料难拼焊、结构难成形和精度性能难控制等问题，开展高强铝合金搅拌摩擦焊（FSW）拼焊车身构件热冲压成形技术基础研究。通过理论分析、数值模拟与工艺实验，研究铝合金FSW拼焊车身构件热冲压多相异质组织结构及其性能遗传演化规律，揭示科学问题1：FSW拼焊构件热力耦合不均匀变形下多相异质组织结构特征对成形性能的作用机制，建立全流程组织性能稳定化、强韧化热力耦合调控方法；研究铝合金FSW拼焊车身构件热冲压多区不均匀变形特征下成形精度形成机理，揭示科学问题2：FSW拼焊构件热力耦合宏微观不均匀变形特征及其对成形几何精度的作用机制，阐明几何精度在多工序成形中的传递和演变规律，建立铝合金FSW拼焊车身构件热冲压不均匀变形下组织性能和几何精度的预测与调控理论方法，为铝合金拼焊车身构件成形成性提供科学依据，促进我国汽车轻量化技术的应用与发展。

本项目紧密结合汽车轻量化国家重大需求，针对复杂曲面薄壁铝合金拼焊车身构件材料难拼焊、结构难成形和精度性能难控制等工程问题，开展了高强铝合金搅拌摩擦焊（FSW）拼焊车身构件热冲压成形技术基础研究。通过理论分析、数值模拟与工艺实验，研究了铝合金FSW拼焊车身构件热冲压中多相异质组织结构及其性能遗传演化规律，揭示了FSW拼焊构件热力耦合不均匀变形下多相异质组织结构特征对成形性能的作用机制，建立了全流程的组织性能稳定化、强韧化热力耦合调控方法；研究了铝合金FSW拼焊车身构件热冲压多区不均匀变形协调下成形精度演变规律，建立了铝合金FSW拼焊车身构件热冲压不均匀变形下组织性能和几何精度的预测与调控方法，为铝合金拼焊车身构件成形成性提供科学依据，促进我国汽车轻量化技术的应用和发展。项目研究期间发表论文18篇（第一标注16篇），其中SCI 论文13篇（含Top1期刊1篇，JCR1区论文 7篇），EI论文5篇；授权中国发明专利9项；人才培养共11人，其中青年教师1名，博士后1名（出站留校工作），博士研究生1名，硕士研究生8名，上述研究生均已毕业并取得学位。各结题指标均超额完成。基于项目发明了异质铝合金拼焊热冲压成形成套技术方法，解决了铝合金拼焊热成形晶粒异常长大、成形性差等难题，开发了国内首款高强铝合金变强度高强韧铝合金拼焊热成形车身构件，研究成果已转化东风（武汉）实业有限公司。