Role of aging time and Cu/Zn additions on the microstructure and intergranular corrosion resistance of 6082 Al-Mg-Si alloy

The influence of aging time (1, 2, 5, and 24 h) and minor additions of Cu (≤ 0.05 wt%), Zn (≤ 0.06 wt%), and Cu/Zn on the microstructure and intergranular corrosion (IGC) resistance of Al-Mg-Si alloy is investigated. Minor Cu or Zn additions negatively affect IGC resistance of these alloys. However, the findings also indicate that a Cu/Zn ratio of approximately 1.54 enhances corrosion resistance across aging conditions, which can be further improved by appropriate heat treatments. Additionally, STEM-EDS analysis indicates that Zn is less detected in grain boundaries (GBs) and intragranular precipitates compared to Cu at identical aging conditions. • Peak hardness of Al-Mg-Si alloy increases with minor Cu/Zn addition. • IGC resistance decreases with increased Cu/Zn individually. • Aging time significantly affects grain boundary chemistry, even with minor Cu/Zn additions.