(1. 哈尔滨工业大学 材料科学与工程学院,哈尔滨150001;
2. 中国科学院 金属研究所,沈阳 110016)
摘 要: 通过分析旋转喷吹除气过程中氢在惰性气泡表面和金属熔体/空气界面的质量传输,建立适用于镁合金旋转喷吹除气的理论模型。通过计算,分析工艺参数对除气效率的影响。结果表明:随着旋转喷吹转速由230 r/min增大到330 r/min时,熔体中气泡总表面积由1.49×10−2 m2增大到3.44×10−2 m2,这增大了熔体中氢向气泡的单位时间扩散量,从而使除气效率随着转速的增加而增大。利用减压凝固方法对旋转喷吹除气的效果进行实验验证,实验结果与理论模型计算结果吻合较好。该模型可以用来指导镁合金熔体除气工艺的优化。
关键字: AZ91镁合金;旋转喷吹;除气;熔体净化
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. Institute of Metal Research Chinese Academy of Sciences, Shenyang 110016, China)
Abstract:A theoretical model was established for the degassing of magnesium alloy by a spinning spray based on the analysis of the mass transformation of hydrogen at the surfaces of Ar gas bubbles and the interface between the melt and air. The effect of the process parameters, such as the rotation speed on the degassing efficiency was calculated and analyzed. The results show that the total surface area of the gas bubbles increases with increasing rotation speed of spinning, i.e. the total surface area increase from 1.49×10−2 m2 to 3.44×10−2 m2 with increasing rotation speed from 230 r/min to 330 r/min. As a result, the diffusion content of hydrogen increases with rotation speed increasing, and the degassing efficiency increases. Verification experiment was conducted by measuring the density of the samples solidified under a reduced pressure. The theoretical predication is in good agreement with the experimental results, suggesting that the model could be used for the optimization of degassing processes of magnesium alloy.
Key words: AZ91 magnesium alloy; spinning spraying; degassing; melt purification