紫外光对铝合金焊接接头腐蚀行为的影响

通过光学显微镜分析研究了6061铝合金熔化极惰性气体保护焊(metal inter gas welding, MIG焊)和搅拌摩擦焊(friction stir welding, FSW)对接头组织的影响.结合极化曲线测试，比较了紫外光照射与暗态对预沉积NaCl的基材及焊接接头腐蚀行为影响的差异.结果表明，MIG焊接头组织均匀性较差，焊缝Mg含量远高于母材，使得表现出较差的热力学稳定性.紫外光照射加速了铝合金焊接接头的腐蚀，尤其是明显加速了MIG焊接头的腐蚀.30天的紫外光照射对FSW接头的影响与母材相近.这些影响与材料本身的耐腐蚀性能及铝合金表面形成的半导体性质腐蚀产物密切有关.

Effect of UV light on the corrosion behaviors of aluminum alloy welded joints

The effects of metal inert gas (MIG) welding and friction stir welding (FSW) on the microstructure of 6061 aluminum alloy were studied by OM. Meanwhile, combined with the polarization curves test, the corrosion behaviors of the base metal and welded joints of pre-deposited NaCl after exposure under ultraviolet light (UV) irradiation and in the dark were compared. The results showed that the uniformity of the MIG welded joint microstructure was poor, and the content of Mg in weld zone was much higher than that in base metal. So the MIG welded joint showed the poor thermodynamic stability. UV irradiation could accelerate the corrosion rate of the base metal and the welded joints, in particular, the MIG welded joint was significantly affected. The effect of 30 days UV irradiation on the FSW joint was similar to that of the base metal. These effects are closely related to the corrosion resistance of the material and the corrosion products of semiconductor properties formed on the surface of the aluminum alloy.