Flow behavior and processing maps of 2099 alloy

The flow behavior of 2099 alloy was investigated by means of hot compression tests in the temperature range of 300-500 degrees C and strain rate range of 0.001-10 s(-1). Processing maps were developed on the basis of the dynamic materials model (DMM). The results show that the flow stress increases with increasing strain rate and decreasing temperature. At a given deformation condition, the flow stress composed three stages: work hardening stage, softening stage and steady stage. Microstructure observation indicates that in the deformation temperature range of 300-420 degrees C and strain rate of 0.001-10 s(-1) shows a dynamic recovery (DRV) character; while that deformed in the deformation temperature range of 420-500 degrees C and strain rate of 0.001-10 s(-1) shows a dynamic recrystallization (DRX) character. According to the processing map and microstructure observation, DRV and DRX are the main deformation mechanisms in the safe regions, while flow instability is manifested as adiabatic shear bands and flow localization at the strain of 0.7. The optimum processing parameters for 2099 alloy at different strains conditions are given with the efficiency dissipation more than 0.3. (C) 2014 Elsevier B.V. All rights reserved.