Atomic-resolution electron energy loss studies of precipitates in an Al–Mg–Si–Cu–Ag alloy

Aberration-corrected scanning transmission electron microscopy combined with electron energy loss spectroscopy has been used to determine the distribution of Cu and Ag atomic columns of precipitates in an Al–Mg–Si–Cu–Ag alloy. Cu columns were commonly part of C and Q′ phases, with the atomic columns having large projected separations. Columns containing Ag were more tightly spaced, in areas lacking repeating unit cells and at incoherent precipitate–host lattice interfaces. Cu-rich and Ag-rich areas were not found to intermix.