目的 研究 Fe 对铝镁焊料晶间腐蚀的影响规律，确定 Fe 元素的最佳含量。 方法 制备不同 Fe元素含量的铝镁合金并进行表面处理， 在 3%（质量分数） NaCl+10 mL/L HCl 溶液中（35 ℃）浸泡 24h，进行晶间腐蚀实验。通过扫描电子显微镜和光学显微镜对晶间腐蚀形貌和合金相进行分析。 结果 随着 Fe 元素含量的增加，合金试样最大腐蚀深度由 133 μm 增加到 179 μm； Fe 元素质量分数超过 0.2%后， 合金发生晶间腐蚀倾向大幅增加。引入 Fe 元素后，铝镁焊料合金相由 α（Al）基体相+Al3Mg2相转变为 α（Al）相+Al3Mg2相+ FeAl3相。随着 Fe 元素含量的增加，合金中富 Fe 相（FeAl3）析出量增加， FeAl3相形貌由最初的骨骼状转变为针片状和针状。 FeAl3相的增加提升了合金发生晶间腐蚀的原动力，增加了合金发生晶间腐蚀的敏感性。 结论 在铝镁焊料合金中引入 Fe 元素后，合金组织发生改变，导致合金抗晶间腐蚀能力下降。 为降低合金发生晶间腐蚀的敏感性，应将 Fe 元素质量分数控制在0.2%以下，且越低越好。

Objective To research the influencing law of Fe element on intergranular corrosion of Al-Mg filler metal, and determine the desirable Fe content of filler metal. Methods In this paper, Al-Mg alloys with different Fe addition were prepared. The surface of alloys was modified and then immersed into 3%NaCl (mass fraction)+10 mL/L HCl aqueous solution for 24 hours at 35 ℃ to perform intergranular corrosion (IGC) experiments. Their morphologies were studied by SEM and Optical microscopy (OM). Results Maximum intergranular corrosion depths of alloys were improved from 133 μm to 179 μm by adding Fe. The intergranular corrosion resistance obviously decreased when the Fe content exceeded 0.2%. The original phase composition of alloys were transformed from α(Al)+Al3Mg2 into α(Al)+Al3Mg2+FeAl3 with increasing Fe content. The morphology of FeAl3 phase changed from skeleton into needle. The Al-Mg filler metal possessed high intergranular corrosion susceptibility with the increase of Fe-rich phases, which increased the motive force of intergranular corrosion. Conclusion The addition of Fe element could lead to structure change and thus reduce the intergranular corrosion resistance of alloys. To obtain high intergranular corrosion resistance, the Fe content in the alloy should be further reduced below 0.2%, and the lower the better.