Investigation of AA2024-T3 surfaces modified by cerium compounds: A localized approach

• The precipitation of cerium compounds occurs on the entire AA2024-T3 surface.
• The matrix is less involved in the cerium precipitation.
• Cerium intensely precipitates on Mg-rich IM particles.
• The electrochemical behavior of Mg-rich IM particles influences the mechanism of cerium precipitation.

The precipitation of cerium compounds on polished AA2024-T3 surfaces was investigated following an electrochemical and microstructural localized approach. It was found that cerium precipitation occurs on the entire surface covering intermetallic particles and the matrix as well. The matrix is the region where the precipitation of cerium is less favoured. The highest amount of cerium was observed on magnesium-rich intermetallic particles. The localized analyses suggest that precipitation of cerium on magnesium-rich intermetallic particles could happen following two mechanisms: the former based on a potential reversal of the intermetallic particles and the latter due to a partial magnesium dissolution.