Abstract In this work, the influences of Fe, Mn and Y with various contents on microstructural evolution and mechanical properties of hypoeutectic Al–7%Si alloy were investigated by microscopy technology and tensile test. The results showed that the complex addition of Al–20%Si-2.5%Fe–2%Mn master alloy and rare earth Y have much better refining effect of need-like eutectic Si and coarse α-Al dendrites than that of separate addition of master alloy or rare earth Y. Combined additions of 7.0% master alloy and 0.2% Y, the average grain size was decreased by 89.5% from 483.1 μm to 50.8 μm and secondary dendrite arm spacing (SDAS) was reduced by 46.8% from 26.9 μm to 14.3 μm. Moreover, the coarse flake-like eutectic Si structure was effectively modified into fine fiber and granular shape. In addition, ultimate tensile strength (UTS) was improved by 33.3% from 162 MPa to 216 MPa, and elongation (El) value was enhanced by 46.7% from 6.2% to 9.1%. The fracture mode transformed from brittle fracture to ductile fracture.

中文翻译：

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Fe、Mn、Y添加量对亚共晶Al-7%Si合金组织和力学性能的影响

摘要 本工作通过显微技术和拉伸试验研究了不同含量的Fe、Mn和Y对亚共晶Al-7%Si合金组织演变和力学性能的影响。结果表明，Al-20%Si-2.5%Fe-2%Mn中间合金和稀土Y的复合添加比单独添加具有更好的需要状共晶Si和粗α-Al枝晶的细化效果。中间合金或稀土 Y。 7.0% 中间合金和 0.2% Y 的组合添加，平均晶粒尺寸从 483.1 μm 减小到 50.8 μm，降低了 89.5%，二次枝晶臂间距 (SDAS) 从 26.9 μm 减小了 46.8%到 14.3 微米。此外，粗片状共晶硅结构被有效地改性为细纤维和颗粒状。此外，极限拉伸强度 (UTS) 提高了 33。3% 从 162 MPa 提高到 216 MPa，伸长率 (El) 值提高了 46.7%，从 6.2% 提高到 9.1%。断裂方式由脆性断裂转变为韧性断裂。