Quantitative evaluation of the effect of Ag-addition on the concurrently-existing precipitation kinetics in the aged Al-Cu-Mg(-Ag) alloys

•SAXS study quantitatively evaluated the effect of Ag-addition on the concurrently-existing precipitation kinetics in the aged Al-Cu-Mg(-Ag) alloys.•Nanoscale disk-like Mg-Ag co-clusters (2.3 nm in diameter and 6.1 Å in thickness) were quantitatively examined by SAXS.•An increasing aspect ratio of Ω-precipitates with a nearly constant thickness (<2 nm) was quantitatively revealed by SAXS.•Stable structure behaviors in total surfaces/sizes of S-precipitates represented the effect of Ag-addition providing the resistance to the coalescence/coarsening mechanism.