Characterization of hot deformation behavior of AA2014 forging aluminum alloy using processing map
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: The hot deformation behavior of AA2014 forging aluminum alloy was investigated by isothermal compression tests at temperatures of 350-480？°C and strain rates of 0.001-1？s-1 on a Gleeble-3180 simulator. The corresponding microstructures of the alloys under different deformation conditions were studied using optical microscopy (OM), electron back scattered diffraction (EBSD) and transmission electron microscopy (TEM). The processing maps were constructed with strains of 0.1, 0.3, 0.5 and 0.7. The results showed that the instability domain was more inclined to occur at strain rates higher than 0.1 s-1 and manifested in the form of local non-uniform deformation. At the strain of 0.7, the processing map showed two stability domains: domain I (350-430？°C, 0.005-0.1？s-1) and domain II (450-480？°C, 0.001-0.05 s-1). The predominant softening mechanisms in both of the two domains were dynamic recovery. Uniform microstructures were obtained in domain I, and an extended recovery occurred in domain II, which would lead to the potential sub-grain boundaries progressively transforming into new high-angle grain boundaries. The optimum hot working parameters for the AA2014 forging aluminum alloy were determined to be 370-420？°C and 0.008-0.08？s-1.
Key words: AA2014 aluminum alloy; hot deformation behavior; constitutive model; processing map; softening mechanism