Mn和Mg对Al-5Fe合金初生Al3Fe相形貌的影响

Mn和Mg添加到Al-5Fe(质量分数，％，下同)合金中，初生Al3Fe相的形貌发生明显变化．未加入合金元素时，该合金中的初生Al3Fe相长成粗大的针片状；加入2．5％Mn和0．1％Mg(质量分数，下同)后，粗大的初生富铁相消失，取而代之的是细小针状、粒状和花朵状；加入2．5％Mn和1．5％Mg，合金中的富铁相大部分转变为粒状和穗状(分叉状)两种．探讨了粒状和穗状的形成机理．对合金力学性能的测试表明，加入Mn和Mg后，合金的抗拉强度得到了不同程度的提高：Al～5Fe合金为107MPa，Al-5Fe-2．5Mn-0．1Mg合金为139MPa，Al-5Fle-2．5Mn-1．5Mg合金为122MPa，增长幅度分别为29．9％和14％．

EFFECT OF Mn AND Mg ON THE MORPHOLOGY OF PRIMARY Al3Fe PHASE IN Al-5Fe ALLOY

Adding Mn and Mg in Al-5Fe(mass fraction, %) alloy has obvious effect on the morphology of the primary Al3Fe phase which is thick needle plate-like before adding alloyed elements. The addition of 2.5% Mn and 0.1% Mg(mass fraction) changes the primary Al3Fe phase from thick needle plate-like to fine needle-like, particle-like and flower-like; the additon of 2.5% Mn and 1.5% Mg forms particle-like and fringe-like (bifurcated), the forming mechanism of which was analysed. The mechanical property is raised after the addition of Mn and Mg: the tensile strength of Al-5Fe alloy is 107 MPa, Al-5Fe-2.5Mn-0.1Mg alloy 139 MPa and Al-5Fe-2.5Mn-1.5Mg alloy 122 MPa. The properties are increased by 29.9% and 14% respectively compared with that of Al-5Fe alloy.