Hot deformation behavior and workability characteristic of a fine-grained Mg–8Sn–2Zn–2Al alloy with processing map
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第6期
论文作者：Weili Cheng Yang Bai Shichao Ma Lifei Wang Hongxia Wang Hui Yu
文章页码：1198 - 1209
摘 要：The hot deformation behavior of a fine-grained Mg–8 Sn–2 Zn–2 Al（TZA822, in wt%） alloy was investigated in the temperature range of 150–350°C and the strain rate of 0.01–10 s-1 employing thermomechanical simulator. In most of the cases, the material showed typical dynamic recrystallization（DRX） features i.e., a signal peak value followed by a gradual decrease or to reach a steady state. The work hardening rate was found to increase with decreasing temperature and increasing strain rate, while strain rates had great effects on work hardening behavior. Meanwhile, the constitutive analysis indicated that cross-slip of dislocations was likely to be the dominant deformation mechanism. In addition, the processing map at the strain of 0.1–0.7 showed two stability domains with high power dissipation efficiencies and the optimum hot working parameters for the studied alloy was determined to be 350°C/0.01 s-1 and 350°C/10 s-1, at which continuous DRX（CDRX） and discontinuous DRX（DDRX） as main softening mechanism. The instability regions occurred at 200–250°C/10 s-1 and the main flow instability mechanism was twinning and/or flow localization bands, which were prone to induce cracks and caused in-consistent mechanical properties of the alloy.
Weili Cheng，Yang Bai，Shichao Ma，Lifei Wang，Hongxia Wang，Hui Yu
摘 要：The hot deformation behavior of a fine-grained Mg–8 Sn–2 Zn–2 Al（TZA822, in wt%） alloy was investigated in the temperature range of 150–350°C and the strain rate of 0.01–10 s-1 employing thermomechanical simulator. In most of the cases, the material showed typical dynamic recrystallization（DRX） features i.e., a signal peak value followed by a gradual decrease or to reach a steady state. The work hardening rate was found to increase with decreasing temperature and increasing strain rate, while strain rates had great effects on work hardening behavior. Meanwhile, the constitutive analysis indicated that cross-slip of dislocations was likely to be the dominant deformation mechanism. In addition, the processing map at the strain of 0.1–0.7 showed two stability domains with high power dissipation efficiencies and the optimum hot working parameters for the studied alloy was determined to be 350°C/0.01 s-1 and 350°C/10 s-1, at which continuous DRX（CDRX） and discontinuous DRX（DDRX） as main softening mechanism. The instability regions occurred at 200–250°C/10 s-1 and the main flow instability mechanism was twinning and/or flow localization bands, which were prone to induce cracks and caused in-consistent mechanical properties of the alloy.
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