Effects of aging time on corrosion behavior of an Al-Cu-Li alloy

Abstract Here, we revealed the effect of different precipitates on the corrosion behavior of an Al-Cu-Li alloy through quasi-in-situ transmission electron microscopy observation. The corrosion mode changed from inter-granular to intra-granular as the aging time at 160 °C increased. The decreased susceptibility to inter-granular corrosion was due to the precipitation of anodic T1 precipitates after 104 h aging, balancing the potential difference between grain interior and boundary. Rapid corrosion of T1 led to corrosion striations. Cubic Al5Cu6Li2 precipitates increased notably after aging for 242 h. Corrosion cavities were formed by the dissolution of the Li-enriched layer in Al5Cu6Li2 and the neighboring matrix.