(華南理工大學 材料科學與工程學院，廣州 510640)
摘 要: 采用光學和掃描電子顯微鏡研究了3種添加劑Mg-10Mn、Al-20Mn和MnCl2對Mg-3Al%合金組織的影響，利用相提取技術分析不同錳添加劑下Mg-3%Al(質量分數(shù))合金中生成的Al-Mn相，并通過邊邊匹配模型對Al-Mn相和α-Mg間的晶體學錯配度進行計算。結果表明：不同錳添加劑對Mg-3%Al合金晶粒和Al-Mn相類型有顯著影響。Mg-10Mn和Al-20Mn中間合金在Mn加入量為0.3%時，對Mg-3%Al合金晶粒有一定的細化作用，而MnCl2導致晶粒顯著粗化。Mn加入量為0.3%時，添加Mg-10Mn和Al-20Mn中間合金形成的Al-Mn相主要為Al8Mn5；而Mn量增至0.5%時，添加Mg-10Mn和Al-20Mn中間合金形成的Al-Mn相則主要為Al0.89Mn1.11。添加MnCl2時，Mg-3Al%合金中形成的Al-Mn相主要為Al10Mn3。晶體學錯配度計算表明：Al8Mn5能充當Mg-3%Al合金的異質形核核心，但形核效率一般，Al0.89Mn1.11和Al10Mn3不能充當異質形核核心。
關鍵字: Mg-3Al%合金；晶粒細化；錳添加劑；相提取；邊邊匹配模型
（School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The effects of three kinds of manganese additions on microstructure of the Mg-3Al% alloy were studied by optical microstructure and scanning electron microscope. The phase extracting method was utilized to analyze the Al-Mn phases generated in Mg-3Al% alloy modified by different manganese additions. The crystallography misfits between Al-Mn phases and α-Mg were calculated by using edge-to-edge matching model. The results show that different manganese additions can obtain different grain refinement efficiency and Al-Mn phases for the Mg-3Al% alloy. The grain size of the alloy can be slightly refined by Mg-10Mn and Al-20Mn master alloys when Mn addition is 0.3%. However, the grain is obviously coarsened after being modified by MnCl2. The Al-Mn phase generated in the alloy modified by Mg-10Mn and Al-20Mn master alloys mainly contains Al8Mn5 when Mn addition is 0.3%. And the Al-Mn phase turns to be Al0.89Mn1.11 when Mn addition is 0.5%. When the alloy is modified by MnCl2, the Al-Mn phase is mainly Al10Mn3. The crystallography misfit results show that Al8Mn5 can act as crystallize nuclei with impotent effect. Al0.89Mn1.11and Al10Mn3 cannot act as crystallize nuclei. The results correspond with the grain refinement efficiency of Mg-3Al% alloy modified by different Mn additions.
Key words: Mg-3Al% alloy; grain refinement; manganese addition; phase extraction; edge-to-edge matching model
