Fabrication of 6-filament MgB2 wires enhanced by high strength 91-filament Cu-Nb composite
Résumé
We chose high strength and high conductive Cu-Nb composite as strengthening core to improve the mechanical properties of 6-filament MgB2 wires. The Cu-Nb core become partially dispersion strengthened during the fabrications of the MgB2 wires. It has been found that this Cu-Nb composite offers good promise of increased strength while maintaining the superconducting properties of the MgB2 wire. The Young's modulus of the best wire samples increased significantly to about 130 GPa, which is comparable to those of high strength ferromagnetic materials sheathed wires but without negative ferromagnetic effects. Those mechanical properties were enough to satisfy the low field application needs. The critical current Ic also achieves 200 A (engineering critical current density, Jce above 1.30 9 104 A/cm2) at 20 K 1 T field. The 91-filament Cu-Nb composite core reinforced wires were fabricated by in situ Powder In Tube method.