Manganese (Mn) generally is widely recognized for its effect on modifying the size and morphology of coarse Fe-rich constituents in Al-based alloys by forming fine Mn-rich dispersoids. However, this study suggests that in a Cd-micraolloyed Al-Cu-Mn-based alloy, Mn-rich dispersoids significantly promote Cu-rich precipitation at the interface during artificial aging (AA), leading to undesirable solute consumption of Cu and potential suppression of nanoprecipitation. With the help of atomic-resolution high-angle annular dark-field (HAADF) scanning...