Creep behavior and microstructural evolution of deformed Al-Cu-Mg-Ag heat resistant alloy

The creep behavior of Al-Cu-Mg-Ag alloy and its microstructural evolution during creep deformation were studied at 100-210 degrees C with the external stress of 150-300 MPa. The results show that both Omega, and theta' 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 degrees 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 102.00 kJ/mol. (C) 2014 Elsevier B.V. All rights reserved.