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Highlights: [•] The initial hardening rate was reduced with external stress during aging. [•] Stress-aging can accelerate the precipitation of θ ′ but restrain that of Ω. [•] Prior deformation can also accelerate the precipitation of θ ′ but restrain that of Ω. [Copyright &y& Elsevier]

The creep behavior of Al–Cu–Mg–Ag alloy and its microstructural evolution during creep deformation were studied at 100–210°C with the external stress of 150–300MPa. The results show that both Ω and precipitate secondarily in the under-aged sample during the creeping process, resulting in the excellent creep-resistant property compared to the peak aged sample. The temperatures between 100 and 150°C have little affect on the creep curves of the alloy. The larger external stress led to the growth of the creep holes on the grain boundaries and the higher creep temperature led to the growth of the precipitations in the grains inner. They both result in the lower creep resistance of Al–Cu–Mg–Ag alloy. The steady creep rate increased with increasing creep temperature or external stress, which can be described by a constitutive equation with the creep deformation activation energy 102.00kJ/mol. [ABSTRACT FROM AUTHOR]