Thin Foil Penetration Technique at a Local Scale: Towards an Analysis of the Current Transients during Intergranular Propagation on AA2024 Alloy

Abstract

A local electrochemical probe was combined with the thin foil penetration technique to study the corrosion propagation of a reduced number of grain boundary traces (in-plane) propagating inside a 60μm thick foil of AA2024. This local and "in-volume" approach allowed analysis of the current transient resulting from the full penetration of the selected intergranular paths. By coupling a 2D spatially resolved electrochemistry to digital optical observation on the back side of the foil, it was possible to relate the current transient to the successive steps of the "in-volume" propagation of intergranular corrosion.