Effect of Pre-Stretching on Microstructures and Mechanical Behaviors of Creep-Aged 7055 Al Alloy and Its Constitutive Modeling

Abstract

The rational pre-stretching can contribute to obtaining better mechanical properties. This paper studies the effect of creep stain, mechanical properties, and microstructures of 7055 alloy under different pre-stretching conditions. The results show that compared with solid-quenched alloy, the 7055-T6 alloy is the optimal scheme to attain more creep strain, and the range of pre-stretching from 1.6% to 3.3% is suitable for creep-aged 7055-T6 alloy to obtain better mechanical properties. Further examination by TEM test shows that pre-stretching promotes the formation of dislocations, which provides superior nucleation regions for ή phase resulting in a higher strength alloy. Meanwhile, a unified creep-aging constitutive model for 7055-T6 alloy is established which can be used to accurately predict its creep behavior under the different pre-stretching.