Effects of multi-microalloying (Mn, Zn, Ti) on microstructural evolution of 2060 Al–Cu–Li alloy from casting to aging and its T6 peak-aging mechanical properties

The pursuit of lightweight and high-performance aerospace materials has driven the development of 2060 Al-Cu-Li alloy, yet optimizing their microstructure and properties through multi-microalloying remains a challenge. This study systematically investigates the interrelated contributions of multi-microalloying (Mn, Zn, Ti) on the microstructural evolution and mechanical properties of a 2060 Al-Cu-Li alloy throughout the entire processing chain from casting to T6 peak-aging. While the individual roles of Mn, Zn, and Ti in Al alloys are known, their combined influence across the complete manufacturing route for this alloy system remains less explored. Compared with the base alloy, the multi-microalloyed variant exhibits significant grain refinement in the as-cast state. During homogenization, the multi-microalloyed alloy shows improved dissolution of non-equilibrium phases. After solution treatment, both alloys recrystallize completely, with the modified alloy displaying a slightly finer grain size. In the T6 peak-aged condition, the multi-microalloyed alloy possesses a higher number density and finer distribution of T1(Al 2 CuLi) precipitates, accompanied by Zn enrichment on a fraction of T1 plates. Consequently, the peak-aged multi-microalloyed alloy achieves superior mechanical properties: yield strength increases by ∼14%, ultimate tensile strength by ∼8%, and elongation by ∼28% compared to the base alloy. These improvements are attributed to the interrelated contributions of grain refinement, reduced Fe segregation, enhanced homogenization, and particularly the role of Zn in refining and stabilizing T1 precipitates. Notably, Zn not only promotes a denser and finer distribution of T1 precipitates but also segregates at the T1/matrix interface, thereby enhancing both strengthening and ductility, an interrelated contribution that underscores the value of multi-microalloying in alloy design. It provides valuable insights for designing high-performance 2060 Al–Cu–Li alloys through strategic multi-microalloying.