铸造Al-Si-Cu-Mg系合金中富铁相的变质处理研究

Study on Modification of Iron-rich Phase in Casting Al-Si-Cu-Mg Alloys

通过单因素和多因素试验、力学性能测试、金相显微组织分析,考察了不同w(Mn)/w(Fe)、w(Cr)/w(Fe)、w(Mn)/w(Cr)及Be对Al-13Si-4Cu-1Mg-0.8Fe合金组织中富铁相形貌,以及力学性能的影响规律。试验结果表明:当Fe为0.8%时,Al-13Si-4Cu-1Mg-0.8Fe合金中富铁相主要以长针状的β-Al5Fe Si形态出现;Mn、Cr单独变质过程中,随着w(Mn)/w(Fe)、w(Cr)/w(Fe)的增加,合金的室温强度均呈现先升后降趋势,而伸长率变化不大;当w(Mn)/w(Fe)比为1.1时,合金的室温强度最大可以达到364 MPa,当w(Cr)/w(Fe)为0.35时,合金的室温强度最大可以达到412 MPa;Mn、Cr复合变质时,当w(Mn)/w(Cr)为2.0时,合金综合力学性能可以达到σb=374 MPa、δ5=3.9%;Mn Be、Cr Be和Be的变质效果对合金力学性能影响的规律为Mn Be>Cr Be>Be>基体。

The effects of the different ratio of w(Mn)/w(Fe), w(Cr)/w(Fe), w(Mn)/w(Cr) and the content of Be on the mechanical properties of Al-13Si-4Cu-1Mg-0.8Fe alloys were studied by single factor and multi factor experiment analysis. The microstructures of iron-rich in the alloys were also analyzed through optical microscope. The results show that the tensile strength of the alloys at room temperature increases at first and then decreases with the increase of w(Mn)/w(Fe) and w(Cr)/w(Fe), can reach 364 MPa when w(Mn)/w(Fe) is 1.1 and 412 MPa when w(Cr)/w(Fe) is 0.35 in single factor experiment.While the elongation has little change. After complex modification with the alloy element Mn and Cr, the comprehensive mechanical properties can reach σb=374 MPa, δ5=3.9% when w(Mn)/w(Cr) is 2.0. The order in the effect of modification on the mechanical properties is Mn Be>Cr Be>Be>matrix.