Abstract:Using dynamic polarization curve testing, microzone electrochemical impedance testing, cyclic immersion testing, and immersion corrosion, combined with TEM and SEM, we investigated the corrosion behavior mechanism of 2219 aluminum alloy stir friction welded joints in a mixed solution environment of 1 mg/L sodium chloride and 0.1 mg/L sodium sulfide. The results indicate that there was no significant mechanical property loss before and after corrosion. The corrosion resistance performance of the weld zone is ranked as follows: WNZ > HAZ/TMAZ > BM. The closer to the WNZ center, the greater the effect of heating, resulting in more dissolution of precipitated phases and increased Cu content in the matrix, thereby reducing the rate of oxidation-reduction reactions. Macroscopic galvanic corrosion in the region caused significant changes in the morphology of the BM, with free Cu2+ ions from the dissolution of the aluminum matrix accelerating corrosion by electron deposition, leading to extensive delamination. Corrosion in the HAZ and the TMAZ falls between the two extremes.