Dynamic restoration mechanism and physically based constitutive model of 2050 Al–Li alloy during hot compression

• Published in: Journal of alloys and compounds 2015-11, Vol.650, p.75-85
• Main Authors: Zhu, Ruihua, Liu, Qing, Li, Jinfeng, Xiang, Sheng, Chen, Yonglai, Zhang, Xuhu
• Format: Article
• Language: English
• Subjects: 2050 Al–Li alloy; Aluminum base alloys; Constitutive model; Constitutive relationships; Deformation; Dynamic precipitation; Dynamic recrystallization; Dynamics; Hot pressing; Mathematical models; Particle stimulate nucleation; Restoration; σ phase
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2015.07.182

Dynamic restoration mechanism of 2050 Al–Li alloy and its constitutive model were investigated by means of hot compression simulation in the deformation temperature ranging from 340 to 500 °C and at strain rates of 0.001–10 s−1. The microstructures of the compressed samples were observed using optical microscopy and transmission electron microscopy. On the base of dislocation density theory and Avrami kinetics, a physically based constitutive model was established. The results show that dynamic recovery (DRV) and dynamic recrystallization (DRX) are co-responsible for the dynamic restoration during the hot compression process under all compression conditions. The dynamic precipitation (DPN) of T1 and σ phases was observed after the deformation at 340 °C. This is the first experimental evidence for the DPN of σ phase in Al–Cu–Li alloys. The particle stimulated nucleation of DRX (PSN-DRX) due to the large Al–Cu–Mn particle was also observed. The error analysis suggests that the established constitutive model can adequately describe the flow stress dependence on strain rate, temperature and strain during the hot deformation process. •The experimental evidence for the DPN of σ phase in Al–Cu–Li alloys was found.•The PSN-DRX due to the large Al–Cu–Mn particle was observed.•A novel method was proposed to calculated the stress multiplier α.