Influence of overlap precipitate on the strength–ductility synergy of the Al–10.0Zn–3.0Mg–2.5Cu alloy with a new aging strategy

Abstract

This paper proposes a new aging strategy in which natural aging, combined with pre-deformation, is embedded between the solid solution and artificial aging. The overlap precipitates (η′−ηd) were formed after this process, which included homogeneous (η′) and heterogeneous precipitates (ηd). The overlap precipitates exhibited a better dislocation storage ability than traditional single precipitates, contributing to their superior work hardening rate and strengthen effect. The ultimate tensile strength and elongation of the representative sample were 800.5 MPa and 7.4%, respectively. Compared to the traditional peak aging sample (770.8 MPa, 3.8%), the strength and ductility of Al–10.0Zn–3.0Mg–2.5Cu alloy were further improved synergistically through regulating overlap precipitates. Notably, the proposed novel aging strategy showed excellent engineering application potential.

Keywords

• Al–Zn–Mg–Cu alloy
• Overlap precipitates
• Pre-deformation
• Strength–ductility synergy