• Addition of 0.3 wt.% Sc to AA7085 alloy significantly enhances strength by refining Al grains and increasing the number density of Al3Sc@Al3(Sc,Zr) core-shell nanoparticles and Sc-containing precipitates.
• First-principles calculations reveal strong strain fields and electron transfer from Zr to Al at the Al3Sc@Al3(Sc,Zr)/Al interface, contributing to the strengthening effect.
• Sc doping suppresses the GP−ηp → ηp transformation, thereby modifying the precipitation sequence and improving age-hardening response.
• Corrosion resistance is improved due to finer grain boundary precipitates and a narrower precipitation-free zone in the Sc-modified alloy.