Effects of early stages of prestretching on the aging kinetics in Al–Cu–Li–based alloy

Abstract A combination of high hardness values and a low energy–consumption preparation method was used to induce the precipitation of the T 1 phase in the Al alloy AA2195. This combination was obtained by subjecting the alloy samples to sequential and early stages of prestretching. Hardness testing and differential scanning calorimetry were employed to explore the behaviours of the hardness and enthalpy values as functions of the prestretching level applied before aging. Results demonstrated that the optimal aging thermomechanical conditions are (1) 150 °C for 10 h after applying prestretching levels of 0%, 1%, and 2% and (2) 150 °C for 20 h after applying prestretching levels of 3% and 4%. Under these conditions, the recorded enthalpy values for the formation of the T 1 phase at prestretching levels of 0%, 1%, and 2% were 2.86, 1.72, and 1.14 J g −1 , respectively and those obtained at prestretching levels of 3% and 4% were 1.43 and 1.27 J g −1 , respectively.