Abstract:The aged characteristics and microstructure of two Al-Cu-Mg-Ag alloys with and without Ce addition are investigated by TEM and mechanical properties test. The results show that trace Ce addition inhibits precipitating process and delays peak aging time. 0.25% Ce additions decrease both tensile strength and ductility. TEM observation shows that the morphology of Ω precipitate can be modified by the small addition of Ce. The trace Ce affects the microstructure by reducing the volume fraction of Ω precipitate. It can be concluded that the intensive interaction between Ce and Cu decreases the Cu atom concentration in alloy matrix and reduces the precipitated kinetics for Ω phase.

Key words: aluminum alloy; aging behavior; microstructure; Ce addition; precipitating kinetics