轻量化多材料汽车车身连接技术进展*

轻量化作为汽车节能减排的重要手段，得到世界各国的高度重视。综合考虑成本、性能及轻量化效果，采用多材料混合车身设计成为未来最为重要的车身轻量化手段。然而，异质材料物理属性差异大，采用传统电阻点焊技术难以实现可靠连接，使得轻量化多材料混合车身的装配面临巨大挑战。通过对比分析典型异质材料之间的物理属性差异，提出异质材料连接必须面临和解决的三大科学挑战，即界面硬脆相问题、电化学腐蚀问题以及变形和应力问题。在此基础上，对机械连接、熔钎焊、固相焊、胶接等四类异质材料连接工艺的研究进展、优缺点、应用现状以及发展趋势等进行综合分析和评价，旨在为多材料汽车车身的设计与制造提供借鉴。

Advances in Welding and Joining Processes of Multi-material Lightweight Car Body

Vehicle lightweighting,as an important means for energy saving and emission reduction,has drawn great attention from all over the world.Considering cost,performance and effect of the lightweighting,a mixed use of different materials,e.g.multi-material design,has become the most significant method of vehicle body lightweighting in the future.However,due to the large difference in physical properties of dissimilar materials,traditional resistance spot welding process can hardly be used to obtain reliable joints,which is posing new challenges to the assembly of multi-material vehicle body.Through comparing and analyzing the differences in physical properties of typical dissimilar materials,three major scientific problems that must be faced and solved for the welding and joining of dissimilar materials are proposed,i.e.,hard and brittle phases at faying surface,galvanic corrosion and distortion and stress.The research progress,advantages,disadvantages,application status and development trends of four kinds of dissimilar material joining processes,i.e.,mechanical joining,welding-brazing,solid-state welding and adhesive bonding were analyzed and evaluated,aiming at providing useful references to the design and manufacturing of lightweight vehicle bodies.