Influence of Aging Treatment on Microstructure and Corrosion Behavior of 2124 Aluminum Alloy Pre-Stretching Plate

The microstructures and corrosion properties of 2124 aluminum alloy pre-stretching plates after aging were investigated using transmission electron microscopy( TEM),intergranular corrosion,exfoliation corrosion and polarization curve tests. The influence of aging treatment on corrosion resistances was analyzed. The results show that,with the increase of aging temperature or aging time,interior precipitates chang from S' phase to S phase. The amount and size of precipitates both increase. After aging at high temperature or for long time,the grain boundary precipitates present chain distribution and become coarser. Moreover,wide precipitate-free zones appear near the grain boundary. Intergranular and exfoliation corrosion resistances decrease and corrosion sensitivity increases with the increase of aging temperature or aging time. With the increase of aging temperature or aging time,alloy is susceptible to corrosion,and its corrosion rate also increases. The effect of aging treatment on corrosion sensitivity is closely related to S' phase,the phase precipitated in grain boundary and precipitate-free zone.