Effect of Major Intermetallic Particles on Localized Corrosion of AA2060-T8

The localized corrosion of AA2060-T8 and the role of two major types of intermetallic particles (IMPs), heterogeneous Al-Cu-Fe-Mn and S-phase (Al2CuMg), were studied using scanning Kelvin probe force microscopy (SKPFM) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Topography and Volta potential maps were collected to determine the corrosion morphology around, and the relative nobility of, the same IMPs before and after sequential exposure to NaCl solution. Chemical compositions and the correlation to SKPFM maps of the representative IMPs and corroded structure were identified using SEM-EDS. These results provide insight into the electrochemical behavior and corrosion mechanism of the Al-Cu-Fe-Mn and S-phase IMPs and associated effects on localized corrosion of AA2060-T8 compared to the legacy AA2024-T3.