Improving creep-age forming ability of AA2219 alloy using asymmetrical rolling
(1. Research Institute of Light Alloy, Central South University, Changsha 410083, China;
2. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
3. State Key Laboratory of Precision Manufacturing for Extreme Service Performance,
Central South University, Changsha 410083, China;
4. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
5. Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China;)
2. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
3. State Key Laboratory of Precision Manufacturing for Extreme Service Performance,
Central South University, Changsha 410083, China;
4. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
5. Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China;)
Abstract: The impacts of asymmetric rolling (ASR) and cold rolling (CR) on the creep-aging behavior of AA2219 alloys were revealed by creep deformation experiments, tensile tests, electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The ASR specimens under creep stress condition of 1.2σ0.2 (σ0.2 is the yield strength) displayed a 50% higher creep strain than the CR specimens. At a creep stress of 0.5σ0.2, the ASR specimens demonstrated remarkably mechanical properties, with a tensile strength of 525 MPa, a yield strength of 338 MPa, and an elongation of 15.2%. This enhancement can be ascribed to the effective grain refinement and promotion of recrystallization after ASR. Notably, ASR resulted in the formation of higher cube textures and a denser forest dislocation structure compared with CR. Additionally, ASR specimens demonstrated a higher density of dispersive, smaller θ′ precipitates and larger average Taylor factors compared with CR specimens.
Key words: AA2219 alloy; asymmetric rolling; creep-aging behavior; texture; precipitate; mechanical properties