Hot Deformation Behavior of AZ40 Magnesium Alloy at Elevated Temperatures
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2017年第6期
论文作者：赖林 张奎 MA Minglong LI Xinggang LI Yongjun SHI Guoliang YUAN Jiawei
文章页码：1470 - 1475
摘 要：Hot compression tests on AZ40 magnesium alloy were conducted on a Gleeble 1500 d hot simulation testing machine in a deformation temperature range of 330 ℃-420 ℃ and a strain rate range of 0.002-2 s-1. Hot deformation behaviors were investigated on the basis of the analysis of the flow stressstrain curves, constitutive equation, and processing map. The stress exponent and apparent activation energy were calculated to be 5.821 and 173.96 k J/mol, respectively. Deformation twins and cracks located in grain boundaries were generated at 330 ℃ and 0.02 s-1, which are associated with a high strain rate and a limited number of available slip systems. With increasing temperature and decreasing strain rate, the twins disappeared and the degree of dynamic recrystallization increased. The alloy was completely dynamically recrystallized at 420 ℃ and 0.002 s-1, with a homogenous grain size of approximately 13.7 μm. The instability domains of the deformation behavior can be recognized by processing maps. By considering the processing maps and characterizing the microstructure, the optimum hot deformation parameters in this experiment were determined to be 420 ℃ and 0.002 s-1.
赖林，张奎，MA Minglong，LI Xinggang，LI Yongjun，SHI Guoliang，YUAN Jiawei
State Key Laboratory for Fabrication and Processing of Nonferrous Metals, Beijing General Research Institute for Nonferrous Metals
摘 要：Hot compression tests on AZ40 magnesium alloy were conducted on a Gleeble 1500 d hot simulation testing machine in a deformation temperature range of 330 ℃-420 ℃ and a strain rate range of 0.002-2 s-1. Hot deformation behaviors were investigated on the basis of the analysis of the flow stressstrain curves, constitutive equation, and processing map. The stress exponent and apparent activation energy were calculated to be 5.821 and 173.96 k J/mol, respectively. Deformation twins and cracks located in grain boundaries were generated at 330 ℃ and 0.02 s-1, which are associated with a high strain rate and a limited number of available slip systems. With increasing temperature and decreasing strain rate, the twins disappeared and the degree of dynamic recrystallization increased. The alloy was completely dynamically recrystallized at 420 ℃ and 0.002 s-1, with a homogenous grain size of approximately 13.7 μm. The instability domains of the deformation behavior can be recognized by processing maps. By considering the processing maps and characterizing the microstructure, the optimum hot deformation parameters in this experiment were determined to be 420 ℃ and 0.002 s-1.
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