The development of superconducting joining technology for reacted magnesium diboride (MgB₂) conductors remains a critical challenge for the advancement of cryogen-free MgB₂-based magnets for magnetic resonance imaging (MRI). Herein, the fabrication of superconducting joints using reacted carbon-doped multifilament MgB₂ wires for MRI magnets is reported. To achieve successful superconducting joints, the powder-in-mold method was employed, which involved tuning the filament protection mechanism, the powder compaction pressure, and the heat treatment condition. The fabricated joints demonstrated clear superconducting-to-normal transitions in self-field, with effective magnetic field screening up to 0.5 T at 20 K. To evaluate the interface between one of the MgB₂ filaments and the MgB₂ bulk within the joint, serial sectioning was conducted for the first time in this type of superconducting joint. The serial sectioning revealed space formation at the interface, potentially caused by the volume shrinkage associated with the MgB₂ formation or the combined effect of the volume shrinkage and the different thermal expansion coefficients of the MgB₂ bulk, the filament, the mold, and the sealing material. These findings are expected to be pivotal in developing MgB₂ superconducting joining technology for MRI magnet applications through interface engineering.

_{反应二硼化镁 (MgB 2} ) 导体的超导连接技术的开发对于磁共振成像 (MRI) 领域无冷冻剂 MgB _{2基磁体的发展仍然是一个关键挑战。}在此，报道了使用用于MRI磁体的反应碳掺杂多丝MgB _{2线制造超导接头。}为了成功实现超导接头，采用了模内粉末方法，其中包括调整灯丝保护机制、粉末压制压力和热处理条件。所制造的接头在自场中表现出清晰的超导到法向转变，有效磁场屏蔽在 20 K 时高达 0.5 T。为了评估接头内MgB ₂细丝之一和MgB ₂块体之间的界面，串行首次在此类超导接头中进行切片。连续切片揭示了界面处的空间形成，这可能是由与 MgB _{2形成相关的体积收缩或体积收缩和 MgB 2}块体、细丝、模具和材料的不同热膨胀系数的综合影响引起的。密封材料。这些发现预计将在通过界面工程开发用于 MRI 磁体应用的 MgB ₂超导连接技术方面发挥关键作用。