High critical current densities of multifilamentary Nb- 46.5w%Ti superconductors

Multiple heat treatment, critical current measurements and transmission electron microscopy were employed in improving the critical current carrying capacity of multifilamentary Nb-46.5w%Ti superconductors. The critical current density measurements at 4.2 K exhibited the values of 2860 A/mm²and 580 A/mm²at magnetic fields of 5 T and 9 T, respectively. The high current carrying capacity of the 5 times heat treated superconductor has been attributed to the improved size distribution of the effective pinning sites.