Corrosion Resistance of 5A06/T2 Dissimilar Metals Joined by Friction Stir Welding

In order to study the corrosion resistance of Al/Cu dissimilar metals joined by friction stir welding, immersion corrosion tests of 5A06-T2 dissimilar weld metal plate of 4 mm in thickness prepared by friction stir welding were carried out. The results indicated that the corrosion resistance of weld zone was worse than that of the parent aluminum alloy, the region of the most serious corrosion was the transition zone of 5A06 and T2 combination, in which groovy corrosion appeared. Electron spectroscopy and XRD phase analysis research showed that the content of Mg was higher in transition zone. The second phase Al4Cu9 appeared in this region, and Al4Cu9 had higher corrosion potential compared with Al metal. Those were the main reasons of serious corrosions of this region.