Evolution of activation energy during hot deformation of AA7150 aluminum alloy

The hot deformation behavior of a homogenized AA7150 aluminum alloy was studied in compression tests conducted at various temperatures (573-723 K) and strain rates (0.001-10 s(-1)). The flow stress behavior and microstructural evolution were observed during the hot deformation process. A revised Sellars' constitutive equation was proposed, which considered the effects of the deformation temperature and strain rate on the material variables and which provided an accurate estimate of the hot deformation behavior of the AA7150 aluminum alloy. The results revealed that the activation energy for the hot deformation of the AA7150 aluminum alloy is not a constant value but rather varies as a function of the deformation conditions. The activation energy for hot deformation decreased with increasing deformation temperature and strain rate. The peak flow stresses under various deformation conditions were predicted by a revised constitutive equation and correlated with the experimental data with excellent accuracy. (C) 2013 Elsevier B.V. All rights reserved.