(郑州大学 物理学院，材料物理教育部重点实验室，郑州 450052)
摘 要: 采用传统熔配法制备不同Zr含量的铸造Al-6.5Si-0.45Mg-xSc(x%=0.3%, 0.45%(质量分数))合金。利用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)及电子万能试验机等，研究Zr对铸造Al-6.5Si-0.45Mg-xSc合金微观组织和力学性能的影响。结果表明：未添加Zr时，Sc对铸造Al-6.5Si-0.45Mg合金的α(Al)相和共晶Si相均有一定的细化和变质作用，且Sc含量较高时，效果更好。向Al-6.5Si-0.45Mg-xSc合金中再加入适量Zr，可改善Sc对合金的α(Al)相和共晶Si相的细化和变质效果。与未加Zr合金相比，Zr的添加可进一步细化Al-6.5Si-0.45Mg-xSc合金的α(Al)相、降低二次枝晶间距(SDAS)、改善共晶Si相形貌和提高合金的拉伸性能，而且，加Zr还能在提高铸造Al-6.5Si-0.45Mg-xSc合金拉伸性能的同时，降低Sc使用量。
关键字: 铸造Al-Si-Mg合金；钪；锆；微观组织；拉伸性能
（Key Laboratory of Materials Physics, Ministry of Education, School of Physics, Zhengzhou University, Zhengzhou 450052, China）
Abstract:Cast Al-6.5Si-0.45Mg-xSc (x%=0.3%, 0.45%) alloys containing different Zr contents were prepared by traditional melting method. The effects of Zr contents on the microstructure and tensile properties of the cast Al-6.5Si-0.45Mg-xSc alloys were investigated by means of optical microscope (OM), scanning electron microscopy(SEM), transmission electron microscope(TEM) and electronic universal testing machine. The results show that Sc has some refining and modifying effects on the α(Al) phase and eutectic Si phase of cast Al-6.5Si-0.45Mg alloys without addition of Zr, and these effects are better when Sc content is higher. Adding proper amount Zr into the Al-6.5Si-0.45Mg-xSc alloy can improve the refining and modifying effects of Sc on the α(Al) phase and eutectic Si phase of the alloy. Comparing with the alloy without addition of Zr, the addition of Zr can further refine α(Al) phase, reduce the secondary dendrite arm spacing (SDAS), improve the morphology of the eutectic Si phase and enhance the tensile properties of cast Al-6.5Si-0.45Mg-xSc alloy. In addition, the addition of Zr can also decrease the usage amount of Sc while enhancing the tensile properties of cast Al-6.5Si-0.45Mg-xSc alloy.
Key words: cast Al-Si-Mg-Sc alloy; scandium; zirconium; microstructure; tensile property
