Preparation and Properties of NbTi-Nb3Sn-NbTi Superconducting Joints

NbTi-Nb3Sn-NbTi superconducting joints were fabricated by resistive welding. The microstructure and connecting status were estimated using an X-ray 3D microscopic imaging system online without destroying the joints. The microstructure and grain orientation maps of the Nb3Sn bulk in the joints were tested by electron backscatter diffraction. The Nb3Sn phase exhibited random orientation, and the grain boundaries were mainly composed of high-angle grain boundaries. The resistance of the joints was evaluated under different background fields. Results showed that the resistance was 3 x 10(-13) & omega; under the background field of 3 T.

Automated summary

NbTi-Nb3Sn-NbTi superconducting joints were fabricated by resistive welding, and an X-ray 3D microscopic imaging system was used to evaluate the microstructure and connecting status without destroying the joints. The microstructure and grain orientation maps of the Nb3Sn bulk in the joints were tested by electron backscatter diffraction. The Nb3Sn phase exhibited random orientation, and the grain boundaries were mainly composed of high-angle grain boundaries. The resistance of the joints was evaluated under different background fields, and the resistance was found to be 3 x 10(-13) & omega; under a 3 T background field.