搅拌摩擦焊辅助Al/Zn/Mg接头扩散连接

对2mm厚的AZ31B镁合金和6061铝合金平板进行添加夹层Zn的搅拌摩擦诱导扩散连接实验。通过SEM,EPMA,XRD,拉伸实验和维氏硬度测试研究Al/Zn/Mg搭接接头显微组织和力学性能。结果表明:当旋转速率合适时,扩散层存在Al富集区,Al5Mg11Zn4层及Mg-Zn共晶区;而旋转速率较低时,扩散层存在残留的Zn层;旋转速率过大时,扩散层出现Al-Mg系金属间化合物。由于扩散层主要为金属间化合物,其显微硬度明显高于母材。Zn箔的加入提高了Al/Mg搭接接头的力学性能。断口观察分析表明,接头失效发生在靠近Al侧的扩散层上。

Friction Stir Welding-assisted Diffusion Bond of Al/Zn/Mg Lap Joint

Dissimilar materials welding between 2mm-thick AZ31B Mg alloy and 6061 Al alloy plates in overlap form was performed using the friction stir-induced diffusion bond with zinc foil as the interlayer.The microstructure and mechanical properties of the Al/Zn/Mg lap joints were analyzed by means of SEM,EPMA,XRD,tensile experiment and Vickers hardness test.The results show that diffusion layer consists of Al enrichment zone,Al5Mg11Zn4 layer and Mg-Zn eutectic zone at proper rotation speed;however,when rotation speed is low,the residual zinc interlayer remains in the diffusion layer;when rotation speed is high,the Al-Mg intermetallic compounds are present again.Due to the existence of intermetallic compounds in diffusion layer,its microhardness is significantly higher than that of base metal.The addition of zinc foil can improve the mechanical properties of Al/Mg lap joints.According to analysis on the fracture,joint failure occurs in the diffusion layer near to Al side.