Generation of aluminium–steel joints with laser-induced reactive wetting
Generation of aluminium–steel joints with laser-induced reactive wetting
复制标题
DOI：
10.1016/j.msea.2006.09.111
复制
发表时间：
2007-01
期刊：
影响因子：
6.4
通讯作者：
P. Peyre;G. Sierra;F. Deschaux-Beaume;D. Stuart;G. Fras
中科院分区：
文献类型：
--
作者：
P. Peyre;G. Sierra;F. Deschaux-Beaume;D. Stuart;G. Fras
继德国工人之前的工作之后，一种将钢组装到铝上的新方法被开发出来。在这种新方法中，激光诱导的铝熔池扩散并润湿固体钢，在凝固后生成坚固耐用的界面层。对非镀锌和镀锌 DC04 钢的接头性能进行了研究，包括表面特征、界面微观结构和拉伸试验下的机械阻力。还进行了热和扩散有限元 (FE) 模拟，以计算界面处的温度历史和反应层厚度。发现沿界面形成的2-20μm厚的反应层主要由Fe2Al5金属间化合物组成，具有高硬度（1200HV）和相当低的延展性（存在凝固裂纹）。尽管由于锌蒸发而在熔池中形成闭塞孔，但钢上 10μm 厚的锌层的存在被证明对接头的润湿特性有有益的影响。有限元热模型证明 DC04 低碳钢和 6016 铝板之间的界面润湿温度为 760–1020°C，熔池时间维持在 0.2–0.5 秒范围内，从而产生高速反应动力学。使用这些温度数据，扩散计算可以很好地预测金属间化合物的厚度。考虑对铝钢搭接接头进行拉伸测试，并证明镀锌钢具有更高的机械阻力（220N/mm 线性拉伸强度），前提是在焊接前对钢表面进行助焊处理以避免锌蒸发。相比之下，非镀锌组件表现出低得多的机械阻力（170N/mm，产生 90MPa 的界面剪切强度）。结论是，激光诱导润湿技术是一种无需填充材料即可生成铝钢接头的相当有效的方法，并且应将其视为相对于固体装配模式（搅拌摩擦焊……）具有竞争力的技术。
A new mean of assembling steel to aluminium was developed, following previous work by German workers . In this new method, a laser-induced aluminium melt pool spreads and wets a solid steel, to generate, after solidification a sound and resistant interface layer. Joint properties were investigated, in terms of surface aspects, interface microstructures and mechanical resistances under tensile testing, for non-galvanized and galvanized DC04 steels. Thermal and diffusional finite element (FE) simulations were also carried out to calculate temperature history at interfaces, and reaction layer thickness. The 2–20μm thick reaction layers formed all along the interface were found to be mostly composed of Fe2Al5intermetallic compound with a high hardness (1200HV) and rather low ductility (presence of solidification cracks). The presence of a 10μm thick Zn layer on the steel was shown to have a beneficial influence on the wetting characteristics of the joint, despite the formation of occluded pores in the melt pool due to Zn vaporisation. FE thermal modelling evidenced 760–1020°C wetting temperatures at the interface between DC04 low carbon steel and 6016 aluminium sheets, with time maintains of the melt pool in the 0.2–0.5s range, resulting in high-speed reaction kinetics. Using these temperature data, diffusion calculations were shown to provide a rather good prediction of intermetallic thicknesses. Tensile tests were considered on aluminium–steel lap joints and evidenced higher mechanical resistances (220N/mm linear tensile strength) on galvanized steels, provided that fluxing of the steel surface was carried out prior to welding to avoid zinc vaporisation. Comparatively, non-galvanized assemblies exhibited much lower mechanical resistances (170N/mm resulting in a 90MPa interfacial shear strength). It was concluded that the laser-induced wetting technique is a rather effective way for generating Al-steel joints without filler material, and that it should be considered as a competitive technique versus solid assembly modes (friction stir welding …).