Abstract The effects of neodymium (Nd) addition (0, 0.03, 0.06 and 0.09 wt.%) on the intermetallic microstructure and mechanical properties of Al-7Si-0.3Mg-0.3Fe (wt.%) alloys were investigated in this study. The microstructures of the intermetallic compounds in the alloys were observed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The Nd-rich particles gradually coarsened with increase of Nd addition and attached to the β-AlFeSi phase surface. Besides, the larger Nd-rich particles in the alloys decreased in size and became spherical after T6 heat treatment. In addition, the Nd addition could influence the amount of the π-AlSiMgFe phase by affecting the undercooling of the quaternary eutectic reaction (Liq. → Al + Si + Mg 2 Si + Al 8 FeMg 3 Si 6 ). The amount of the π-AlSiMgFe phase increased when a little (0.03 wt.%) Nd was added, however with the further increasing Nd content, the larger Nd-rich particles often tightly attached on the β-AlFeSi phase surface and reduced the amount of the π-AlSiMgFe phase. Furthermore, the 0.03Nd as-cast alloy had the optimal conditions for the formation of the π-AlSiMgFe and the spherical Nd-rich particles with the ultimate tensile strength about 302 MPa and elongation about 3.1% after T6 heat treatment.

中文翻译：

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添加钕对Al-7Si-0.3Mg-0.3Fe合金金属间组织和力学性能的影响

摘要 本研究研究了钕 (Nd) 添加量（0、0.03、0.06 和 0.09 wt.%）对 Al-7Si-0.3Mg-0.3Fe (wt.%) 合金金属间组织和力学性能的影响。通过扫描电子显微镜（SEM）和能谱仪（EDS）观察合金中金属间化合物的微观结构。随着Nd添加量的增加，富Nd颗粒逐渐粗化并附着在β-AlFeSi相表面。此外，合金中较大的富Nd颗粒在T6热处理后尺寸减小并变成球形。此外，Nd 的添加可以通过影响四元共晶反应的过冷度来影响 π-AlSiMgFe 相的数量（Liq. → Al + Si + Mg 2 Si + Al 8 FeMg 3 Si 6 ）。π-AlSiMgFe 相的量增加一点（0. 03 wt.%) Nd 被添加，然而随着 Nd 含量的进一步增加，较大的富 Nd 颗粒通常紧密地附着在 β-AlFeSi 相表面并减少了 π-AlSiMgFe 相的数量。此外，0.03Nd铸态合金具有形成π-AlSiMgFe和球形富Nd颗粒的最佳条件，T6热处理后极限抗拉强度约为302 MPa，伸长率约为3.1%。