Modification of constitutive model and evolution of activation energy on 2219 aluminum alloy during warm deformation process
(1. Light Alloy Research Institute, Central South University, Changsha 410083, China;
2. Collaborative Innovation Center of Advanced Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083, China;
3. State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China)
2. Collaborative Innovation Center of Advanced Nonferrous Structural Materials and Manufacturing, Central South University, Changsha 410083, China;
3. State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China)
Abstract: To investigate the flow behavior of 2219 Al alloy during warm deformation, the thermal compression test was conducted in the temperature range of 483-573 K and the strain rate range of 0.001-5 s-1 on a Gleeble-3500 thermomechanical simulation unit. The true stress-true strain curves obtained showed that the flow stress increased with the decrease in temperature and/or the increase in strain rate and the softening mechanism primarily proceeded via dynamic recovery. The modification on the conventional Arrhenius-type constitutive model approach was made, the material variables and activation energy were determined to be dependent on the deformation parameters. The modified flow stresses were found to be in close agreement with the experimental values. Furthermore, the activation energy obtained under different deformation conditions showed that it decreased with the rise in temperature and/or strain rate, and was also affected by the coupled effect of strain and strain rate.
Key words: 2219 Al alloy; warm deformation; flow behavior; constitutive model; activation energy