Fe含量对再生铝硅合金组织和性能的影响

    Effects of Fe Content on Microstructure and Properties of Secondary Al-Si Alloys

    • 摘要: 利用金相显微镜、X 射线衍射仪、万能拉伸试验机等研究了Fe 含量对再生铝硅合金组织和性能的影响,并对该合金中富铁相形态进行了定量分析。结果表明:当Fe 含量从0.796%增加到1.301%时,合金组织中二次枝晶臂间距先减小再增大再减小;富铁相形貌的演变过程为紧密汉字状→汉字状+鱼骨状→汉字状+鱼骨状+针状→针状+汉字状→针状;合金中的富铁相面积分数逐渐上涨,富铁相长度不断增长,尤其当Fe 含量从1.022%上升到1.301%,针状β-Fe 相长度显著增长,平均长度最长可达119.5 μm;β-Fe 相的出现导致合金力学性能的显著下降,当Fe 含量增至1.301%时,合金抗拉强度和伸长率相比0.796%Fe 时分别下降26.26%和52.58%。

       

      Abstract: The effects of Fe content on the microstructure and properties of secondar Al-Si alloys were investigated by optical microscope, XRD and universal tensile testing machine, and quantitative analysis of the iron-rich phase morphology in the alloy.The results show that with the Fe content increasing from 0.796%to 1.301%, the secondary dendrite arm spacing in the alloy decreases, then increases and then decreases again.The morphology evolution sequence of iron-rich phase is as follows:compact Chinese script, Chinese script& fishbone-like, Chinese script & fishbone-like & needle-like, needle-like & Chinese script, needle-like; the area fraction of Fe-rich phase gradually increases and the length of Fe-rich phase grows, especially when the Fe content is in the range of 1.022%-1.301%, the length of needle-like β-Fe phase increases significantly, with the longest average length up to 119.5 μm; the appearance of β-Fe phase leads to a sharp decrease in the mechanical properties of the alloy.When Fe content increases to 1.301%, the tensile strength and elongation of the alloy decrease by 26.26%and 52.58%, respectively, compared with that of 0.796%Fe.

       

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