Influence of artificial aging on corrosion of abraded Al-Zn-Mg-Cu alloys...

Surface abrasion has been shown to create altered surface layers (ASLs) that are hundreds of nm thick on all types of Al alloys. Such ASLs have lower corrosion resistance than the underlying substrate of Al-Zn-Mg-Cu alloys. Here, we demonstrate how heat treatments affect the ASL microstructure on abraded Al-Zn-Mg-Cu alloys using transmission electron microscopy and atom probe tomography, and also how the corrosion properties change using electrochemical polarization. High temperature treatments on the abraded bulk samples enhance η phase precipitation in the ASL, leading to a decreased Zn content in the ASL solid solution, which ennobles the ASL breakdown potential.