Flow curve correction and processing map of 2050 Al-Li alloy
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Aerospace Research Institute of Materials and Processing Technology, Beijing 100076, China)
Abstract: Hot compression tests of 2050 Al-Li alloy were performed in the deformation temperature range of 340-500 °C and strain rate range of 0.001-10 s-1 to investigate the hot deformation behavior of the alloy. The effects of friction and temperature difference on flow stress were analyzed and the flow curves were corrected. Based on the dynamic material model, processing map at a strain of 0.5 was established. The grain structure of the compressed samples was observed using optical microscopy. The results show that friction and temperature variation during the hot compression have significant influences on flow stress. The optimum processing domains are in the temperature range from 370 to 430 °C with the strain rate range from 0.01 to 0.001 s-1, and in the temperature range from 440 to 500 °C with the strain rate range from 0.3 to 0.01 s-1; the flow instable region is located at high strain rates (3-10 s-1) in the entire temperature range. Dynamic recovery (DRV) and dynamic recrystallization (DRX) are the main deformation mechanisms of the 2050 alloy in the stable domains, whereas the alloy exhibits flow localization in the instable region.
Key words: 2050 Al-Li alloy; processing map; dynamic recovery; dynamic recrystallization; flow localization