高强铝合金车身覆盖件伺服热冲压成形机理与应用研究

In order to meet the national significant demands of lightweight of automobiles, the auto body panels made in 7000 series high-strength aluminum alloys are taken as the research objects, the Solution Heat Treatment，Forming and Cold-Die Quenching (HFQ) technology and servo press technology are combined on the basis of previous research. A new servo hot stamping technology is proposed and its basic theory and application are then studied. The constitutive equations and forming limit diagram at high temperature, coupled with microstructural characteristics, are established, the evolution rules of microstructure of aluminum alloys, mechanical properties and geometrical precision during the hot stamping process are studied, the quantitative relation between hot stamping deformation conditions and microstructures, mechanical properties and geometrical precision under the complex stress condition are built, the mechanism of coordinated regulation of microstructure, mechanical properties and geometrical precision in hot stamping are revealed for auto body panels made in 7000 series high-strength aluminum alloys. The theory and methods of precision and performance control for auto body panels made in 7000 series high-strength aluminum alloys are built, the application level of high-strength aluminum alloys in lightweight of automobiles are thus promoted.

针对汽车轻量化国家重大需求，以7000系高强铝合金汽车车身覆盖件为研究对象，在前期研究的基础上，将铝合金固溶加热-成形-淬火（HFQ）工艺与伺服冲压技术相结合，提出高强铝合金伺服热冲压成形技术并开展基础理论与应用研究。建立耦合组织特征的高温本构方程与成形极限，研究铝合金覆盖件热冲压全流程中的微观组织、力学性能和几何精度演变规律，建立复杂应力状况下的热冲压成形条件与组织、性能、精度之间的量化关系模型，揭示7000系高强铝合金覆盖件伺服热冲压成形组织、性能、精度协同调控机制，形成高强铝合金车身覆盖件成形控性理论与方法，发展高性能铝合金车身覆盖件成形新技术，促进高强铝合金在汽车轻量化中的应用水平。

针对7000系高强铝合金室温成形性能差、难以制造大型复杂车身覆盖件的现状，本项目将固溶加热-成形-淬火（HFQ）工艺与伺服冲压技术相结合，提出高强铝合金伺服热冲压成形技术并开展基础理论与应用研究。建设了高强铝合金伺服热冲压试验线，研究了板料高温流变行为和摩擦行为，建立了耦合位错密度的本构关系及成形极限，揭示了高强铝合金热力耦合变形过程中的微观组织、力学性能与几何精度演变规律。建立了基于元胞自动机的成形过程动态再结晶演化模型，提出了高强铝合金多级快速时效强化方法。开发了基于急动度和热加工图的伺服热冲压成形工艺设计方法，形成了高强铝合金覆盖件伺服热冲压成形控性理论，成功研制了汽车中立柱、后纵梁等典型车身覆盖件样件。. 在项目执行过程中，发表并标注基金号的学术论文13篇（SCI收录论文9篇）；申请国家发明专利6项，获授权发明专利5项；获软件著作权1项。主办国际学术会议1次，参加国际学术会议3次、国内学术会议2次。培养博硕士研究生7人（毕业5人，即将毕业2人）；培养青年教师及工程师3人，其中项目负责人获省部级科技奖励2项，被聘为武汉理工大学“15551人才工程”青年拔尖人才。本项目完成了计划书中的各项研究目标。. 通过本项目的研究，建立了高强铝合金车身覆盖件伺服热冲压成形控性理论与方法，为高强铝合金覆盖件热冲压成形控性提供了科学依据，具有重要的学术价值和工程实际意义。