Dynamic recrystallization, texture and mechanical properties of high Mg content Al-Mg alloy deformed by high strain rate rolling
(1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Hunan Provincial Key Laboratory of Spray Deposition Technology & Application, Hunan University, Changsha 410082, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
2. Hunan Provincial Key Laboratory of Spray Deposition Technology & Application, Hunan University, Changsha 410082, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: The Al-Mg alloy with high Mg addition (Al-9.2Mg-0.8Mn-0.2Zr-0.15Ti, in wt.%) was subjected to different passes (1, 2 and 4) of high strain rate rolling (HSRR), with the total thickness reduction of 72%, the rolling temperature of 400 °C and strain rate of 8.6 s-1. The microstructure evolution was studied by optical microscope (OM), scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). The alloy that undergoes 2 passes of HSRR exhibits an obvious bimodal grain structure, in which the average grain sizes of the fine dynamic recrystallization (DRX) grains and the coarse non-DRX regions are 6.4 and 47.7 mm, respectively. The high strength ((507±9) MPa) and the large ductility ((24.9±1.3)%) are obtained in the alloy containing the bimodal grain distribution. The discontinuous dynamic recrystallization (DDRX) mechanism is the prominent grain refinement mechanism in the alloy subjected to 2 passes of HSRR.
Key words: Al-Mg alloy; high strain rate rolling; bimodal grain structure; dynamic recrystallization