搅拌摩擦焊接AA6061-AZ31B合金异质接头在搅拌区的电化学腐蚀行为（英文）

Electrochemical corrosion behaviour of stir zone of friction stir welded dissimilar joints of AA6061 aluminium-AZ31B magnesium alloys

异质金属的连接在交通运输领域如燃料消耗降低、材料质量减轻、排放量减少等方面具有较多优越性。然而,采用熔焊工艺对铝、镁合金进行焊接是一个非常复杂的过程。搅拌摩擦焊接方法是一种对铝、镁合金进行连接的有效方法。在搅拌摩擦焊接过程中,铝、镁合金在搅拌区混合,致使合金在该区的耐蚀性能变差。本文作者研究搅拌摩擦焊AA6061-AZ31B合金异质接头的耐蚀性能,通过改变氯离子浓度、Na Cl溶液的p H值和焊接时间对样品进行恒电位极化实验。采用光学显微镜、扫描电镜和X射线衍射技术对样品的腐蚀表面进行表征。结果表明,在所研究的3个参数中,焊接时间对搅拌摩擦焊AA6061-AZ31B合金异质接头耐蚀性能的影响最显著。

Joining of dissimilar metals will offer many advantages in transportation sectors such as fuel consumption,weightreduction and emission reduction.However,joining of aluminium(Al)alloys with magnesium(Mg)alloys by fusion welding processis very complicated.Friction stir welding(FSW)is a feasible method to join these two dissimilar alloys.Mixing these two metalstogether in stir zone(SZ)leads to poor corrosion resistance.In this investigation,an attempt has been made to understand thecorrosion resistance of SZ of FSWed dissimilar joints of AA6061Al alloy and AZ31B Mg alloy.Potentiodynamic polarization testwas conducted by varying chloride ion concentration,pH value of the NaCl solution and exposure time.The corroded surfaces wereanalyzed using optical microscopy,scanning electron microscopy and XRD techniques.Of these three factors investigated,exposuretime is found to be the most significant factor to influence the corrosion behaviour of SZ of friction stir welded dissimilar joints ofAl/Mg alloys.