(中国科学院 金属研究所, 沈阳 110016)
摘 要: 提出一种低压脉冲磁场合金晶粒细化技术，分析常规铸造和半连续铸造条件下，低压脉冲磁场对镁合金凝固组织的影响。结果表明：脉冲磁场对AZ31、AZ91D、AZ80、AM60、AS31和Mg-Gd-Y-Zr镁合金均有显著的细化效果。施加脉冲磁场后，初生α-Mg形态发生明显球化，由粗大、发达的枝晶变为细小的蔷薇状，且溶质偏析显著降低。采用商用ANSYS软件分析了电磁力、流场以及焦耳热对熔体的影响规律，从形核和生长角度分析了脉冲磁场下镁合金晶粒细化机制，依据界面稳定性理论提出了脉冲磁场下镁合金晶粒球化模型。
关键字: 镁合金；组织；晶粒细化；脉冲磁场
low-voltage pulsed magnetic field
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:A new approach, low-voltage pulsed magnetic field (LVPMF) technique, to refine metal materials was developed. The effect of the LVPMF on the solidified structure of magnesium alloys under common casting and direct casting conditions was investigated. The results show that the grain refinement effects on AZ31, AZ91D, AZ80, AM60, AS31 and Mg-Gd-Y-Zr alloys under the LVPMF are obvious. Meanwhile, the morphology of α-Mg is transformed from developed dendrite to fine rosette with the application of LVPMF. The solute segregation in the alloys decreases obviously under the LVPMF. The magnetic force, flow field and Joule heat with the application of LVPMF were analyzed using the ANSYS element software. The grain refinement mechanism of magnesium alloys was discussed in terms of nucleation and growth theories. A model for spheroidization of developed dendrite α-Mg under LVPMF was developed by analyzing the growth behavior of α-Mg dendrite.
Key words: Mg alloy; microstructure; grain refinement; pulsed magnetic field
