(鄭州大學 物理學院，材料物理教育部重點實驗室，鄭州 450052)
摘 要: 采用傳統(tǒng)熔配法制備不同Zr含量的鑄造Al-6.5Si-0.45Mg-xSc(x%=0.3%, 0.45%(質量分數(shù)))合金。利用金相顯微鏡(OM)、掃描電鏡(SEM)、透射電鏡(TEM)及電子萬能試驗機等，研究Zr對鑄造Al-6.5Si-0.45Mg-xSc合金微觀組織和力學性能的影響。結果表明：未添加Zr時，Sc對鑄造Al-6.5Si-0.45Mg合金的α(Al)相和共晶Si相均有一定的細化和變質作用，且Sc含量較高時，效果更好。向Al-6.5Si-0.45Mg-xSc合金中再加入適量Zr，可改善Sc對合金的α(Al)相和共晶Si相的細化和變質效果。與未加Zr合金相比，Zr的添加可進一步細化Al-6.5Si-0.45Mg-xSc合金的α(Al)相、降低二次枝晶間距(SDAS)、改善共晶Si相形貌和提高合金的拉伸性能，而且，加Zr還能在提高鑄造Al-6.5Si-0.45Mg-xSc合金拉伸性能的同時，降低Sc使用量。
關鍵字: 鑄造Al-Si-Mg合金；鈧；鋯；微觀組織；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
