【摘要】 目的 系统探究不同磁场强度对Al-7Si-0.3Mg-1Fe合金微观组织、晶粒尺寸及力学性能的影响，重点分析磁场对富铁相形态的调控作用及其分布规律，以揭示电磁泵技术在铝合金深度除铁和性能优化中的作用机制，为开发高效、环保的铝合金净化工艺提供理论依据。方法 采用直流电磁泵浇注系统浇注试样成型后，沿纵向切割铸锭，分别取顶部（N极区）、中部和底部（S极区）样品，利用金相显微镜（OM）、扫描电子显微镜（SEM）和能谱仪（EDS）观察和分析其微观组织及富铁相形态；采用X射线衍射仪（XRD）鉴定其物相组成；通过万能拉伸试验机测试合金的力学性能（屈服强度、抗拉强度及延伸率）；利用Image Pro Plus软件定量统计晶粒尺寸分布。结果 当磁场强度由150 m T增至200 m T时，中间区域的富铁相由针状β-AlFeSi相转变为鱼骨状α-AlFeSi相；在300 m T条件下，N极和S极区域的富铁相进一步演化为块状β-AlFeSi相。Fe元素分布显著受磁场调控：随磁场强度的增加，两极区域（N、S极）Fe含量富集（300 mT时质量分数达1.25%），中间区域Fe含量则降低（300 mT时降至0.44%）。平均晶粒尺寸随磁场强度的增加而增大：在150 mT时，平均晶粒尺寸约为490μm，在300 mT时，平均晶粒尺寸增至约660μm。磁场增强了晶粒尺寸分布的不均匀性，两极区域晶粒粗化现象更为显著（在300 mT时，S极区晶粒尺寸>800μm的占比达35%）。抗拉强度由150 mT时的173.89 MPa提高至300 mT时的210.67 MPa（增幅约21%）；屈服强度由150 m T时的69.90 MPa增至300 m T时的80.10 MPa。综合力学性能指数（Q值）由150 m T时的256.60 MPa升至300 mT时的284.59 MPa，表明磁场强化显著提升了合金的承载能力。结论 磁场强度的增加有效调控了Al-7Si-0.3Mg-1Fe合金中富铁相的形态演变与分布规律，同时促进了晶粒粗化。这一过程显著提升了合金的力学性能，尤其是抗拉强度与屈服强度。研究表明，电磁泵技术通过定向迁移Fe元素和优化凝固过程，为Al-7Si-0.3Mg-1Fe的高效除铁与性能强化提供了可行的技术路径。更多还原

【Abstract】 The work aims to systematically explore the effects of different magnetic field strengths on the microstructure, grain size, and mechanical properties of Al-7Si-0.3Mg-1Fe alloy, with focuses on analyzing the regulatory effect of the magnetic field on the morphology of iron rich phases and their distribution patterns, to reveal the mechanism of electromagnetic pump technology in deep iron removal and performance optimization of aluminum alloy, and provide a theoretical basis for the development of efficient and environmentally friendly aluminum alloy purification processes. A direct current electromagnetic pump casting system was used. After casting, the ingot was cut longitudinally, and samples were taken from the top(N region), middle, and bottom(S region). The microstructure and iron rich phase morphology were observed and analyzed by metallographic microscope(OM), scanning electron microscope(SEM), and energy dispersive spectrometer(EDS); The phase composition was identified by X-ray diffraction(XRD); The mechanical properties of alloys(yield strength, tensile strength, and elongation) were tested with a universal tensile testing machine; The grain size distribution was qualitatively analyzed by Image Pro Plus software. When the magnetic field strength increased from 150 mT to 200 mT, the iron rich phases in the middle region transformed from needle shaped β-Al Fe Si phases to fishbone shaped α-AlFeSi phases; Under the condition of 300 mT, the iron rich phases in the N-pole and S-pole regions further evolved into block shaped β-AlFeSi phases. The distribution of Fe elements was significantly regulated by the magnetic field: the Fe content in the two pole regions(N and S poles) was enriched with increasing magnetic field strength(up to 1.25% at 300 mT), while the Fe content in the middle region decreased(down to 0.44% at 300 mT). The average grain size increased with the increase of magnetic field strength: the average size was about 490 μm at 150 mT and increased to about 660 μm at 300 mT. The magnetic field enhanced the non-uniformity of grain size distribution, and the phenomenon of grain coarsening in the polar region was more significant(at 300 mT, the proportion of grain size>800 μm in the S region reached 35%). The tensile strength increased from 173.89 MPa at 150 mT to 210.67 MPa at 300 mT(an increase of approximately 21%); The yield strength increased from 69.90 MPa at 150 mT to 80.10 MPa at 300 mT. The comprehensive mechanical performance index(Q value) increased from 256.60 MPa at 150 mT to 284.59 MPa at 300 mT, indicating that magnetic field strengthening significantly improved the bearing capacity of the alloy. In conclusion, the increase in magnetic field strength effectively regulates the morphological evolution and distribution of iron rich phases in Al-7Si-0.3Mg-1Fe alloy, while promoting grain coarsening. This process significantly improves the mechanical properties of the alloy, especially the tensile strength and yield strength. Research has shown that electromagnetic pump technology provides a feasible technical path for efficient iron removal and performance enhancement of Al-7Si-0.3Mg-1Fe alloy by directional migration of Fe elements and optimization of the solidification process.更多还原