Materialia, 2019, vol 8pp. 100429
Precipitation in Duralumin, a historic quaternary alloy of the type: AlCuMgSi, was never fully studied nor observed by current electron microscopy techniques. This article presents the full characterization and comparison of two alloys: a Duralumin (A-U4G) from the 1950s collected on a vintage aircraft and its modern equivalent: a 2017A alloy. The as-received and peak-aging states were analysed with DSC, SAXS and TEM advanced techniques. It is shown that old Duralumin and modern 2017A present a similar nanoprecipitation in the as-received state and behave similarly upon artificial aging. As opposed to what has been reported in the past, three types of precipitates participating in hardening were found upon aging: ?-Al2Cu, Q(Q)-AlCuMgSi and ?-Al2Cu.