Abstract：
The localized corrosion behavior of Al-7.82Zn-1.99Mg-2.41Cu-0.12Zr alloy was investigated. At the early stage of corrosion, the sample surface only suffers slight local pitting corrosion. While as the immersion time extends, intergranular corrosion occurs, accompanied with surface exfoliation. At the initial stage of pitting corrosion, Al and Mg elements in the matrix around Al7Cu2Fe particles are dissolved preferentially, forming Al and Mg deplete zones. Furthermore, the dissolution of Al and Mg elements triggers the selective dissolution of Al element in Al7Cu2Fe, remaining Cu-rich and Fe-rich cluster. Atomic force microscopy (AFM) results show that this Cu-rich and Fe-rich cluster has higher potential difference relative to the matrix than the uncorroded Al7Cu2Fe particle.
