Establishment of hydrogen measurement system for magnesium alloy melt
(1.State Key Laboratory of Material Processing and Die & Mould Technology,Huazhong University of Science and Technology, Wuhan 430074, China
2.湖北省武汉市华中科技大学国家材料加工和模具技术重点实验室
3.State Key Laboratory of Materials Processing and Die & Mould Technology,Huazhong University of Science and Technology, Wuhan 430074, China)
2.湖北省武汉市华中科技大学国家材料加工和模具技术重点实验室
3.State Key Laboratory of Materials Processing and Die & Mould Technology,Huazhong University of Science and Technology, Wuhan 430074, China)
Abstract: The equations of hydrogen solubility in pure magnesium and its alloy were deduced based on thermodynamic analysis: for pure magnesium, lgc(H)=0.5lg p(H2)？1 332/T+0.568; for AZ91 alloy, lgc(H)=0.5lg p(H2)？1 332/T+0.483. Based on the above equations, a rapid and reliable measurement system for hydrogen content in magnesium melt was set up with CPU controller and electric circuit. With this instrument, measurement experiments were carried out to determine hydrogen content in AZ91 melt. The results show that the actual hydrogen level of AZ91 melt under gas protection varies from 0.06 mL/g to 0.14 mL/g at the temperature range from 650 ℃ to 750 ℃, and hydrogen content lineally increases with the increase of temperature.
Key words: magnesium alloy melt; hydrogen content; thermodynamic equation; measurement