(中國(guó)科學(xué)院 金屬研究所, 沈陽(yáng) 110016)
摘 要: 提出一種低壓脈沖磁場(chǎng)合金晶粒細(xì)化技術(shù)，分析常規(guī)鑄造和半連續(xù)鑄造條件下，低壓脈沖磁場(chǎng)對(duì)鎂合金凝固組織的影響。結(jié)果表明：脈沖磁場(chǎng)對(duì)AZ31、AZ91D、AZ80、AM60、AS31和Mg-Gd-Y-Zr鎂合金均有顯著的細(xì)化效果。施加脈沖磁場(chǎng)后，初生α-Mg形態(tài)發(fā)生明顯球化，由粗大、發(fā)達(dá)的枝晶變?yōu)榧?xì)小的薔薇狀，且溶質(zhì)偏析顯著降低。采用商用ANSYS軟件分析了電磁力、流場(chǎng)以及焦耳熱對(duì)熔體的影響規(guī)律，從形核和生長(zhǎng)角度分析了脈沖磁場(chǎng)下鎂合金晶粒細(xì)化機(jī)制，依據(jù)界面穩(wěn)定性理論提出了脈沖磁場(chǎng)下鎂合金晶粒球化模型。
關(guān)鍵字: 鎂合金；組織；晶粒細(xì)化；脈沖磁場(chǎng)
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
