Effect of aging time and temperature on exfoliation corrosion of aluminum alloys 2024-T3 and 7075-T6

摘要

Two types of aluminum alloys, 2024-T3 and 7075-T6, have been selected in this study to investigate the effect of metallurgical aspects on exfoliation corrosion. To determine and evaluate the metallurgical effects of heat treatments on corrosion behaviour of these alloys, G34 ASTM test was selected to investigate the exfoliation corrosion behaviour. The results showed that with increasing the aging time for the aluminum alloy type 2024-T3 the susceptibility to exfoliation corrosion increases, while for type 7075-T6 decreased. These results refer to precipitation of the intermetallic compound phases such as CuAl{sub}2, and MgZn{sub}2, in 2024-T3 and 7075-T6 respectively. The amount of these phases increases with increasing the aging time for both alloys. The investigations showed the phases that initiate in 2024-T3 act as anode sites while in 7075-T6 they act as cathode sites.