Article

Mechanical properties of a niobium-tin superconductor reinforced by tantalum cores

Electrotech. Lab., Tsukuba
IEEE Transactions on Applied Superconductivity (Impact Factor: 1.32). 04/2001; DOI: 10.1109/77.919852
Source: IEEE Xplore

ABSTRACT We have been developing fiber-reinforced type of niobium-tin
superconductor for large scale high field magnets. In this conductor,
each niobium-tin filament has a tantalum core. Tantalum is selected as
material for the core since it has good ductility with mechanical
strength and hence a conventional drawing method can be applied to
fabricate a conductor. Stress-strain characteristics and the
irreversible strain limits of the conductor with different
heat-treatment conditions are measured. Combining these results,
discussions about the mechanical properties of the conductor are
presented

0 Bookmarks
 · 
71 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: A process “continuous wrapping tantalum barrier” has been developing and investigated in this paper. By eliminating the need for inserting expensive tantalum tube, barrier is applied to unlimited piece length prior restack. A tantalum barrier with 20% overlap was wrapped onto subelements. Then 18-filament Nb3Sn plus 1 copper core restack billet was successfully drawn down to wire with 0.84-mm diameter. The longitudinal and cross-sectional images revealed most of barriers were continuous and intact but some disrupted. So, we are still working on the optimization of manufacturing process.
    Journal of Superconductivity 04/2004; 17(2):265-268. DOI:10.1023/B:JOSC.0000021224.74268.12
  • [Show abstract] [Hide abstract]
    ABSTRACT: The capability of the cost-effective process of “continuous wrapping” to prepare tantalum barrier for Nb3Sn multifilamentary wire is investigated in this paper. By eliminating the length limit of inserting a subelement into the expensive tantalum tube, tantalum sheet is wrapped with 20% overlap onto subelement. Then an assembly of 19 restacks was drawn down to the final diameter with 0.8 mm. Two batches of such 19 filamentary assemblies were packed into a copper tube with round and hexangular restacks, respectively. The result has manifested that this continuous wrapping technique can be used to get an intact and continuous tantalum barrier.
    Journal of Superconductivity 06/2004; 17(3):345-347. DOI:10.1023/B:JOSC.0000034256.38248.52
  • [Show abstract] [Hide abstract]
    ABSTRACT: A process, continuous wrapping tantalum barrier, has been developed and investigated in order to reduce the manufacturing cost. By avoiding inserting expensive tantalum tube, a long sheet barrier was directly used to wrap a prior restack. In this work, a tantalum barrier with 20 % overlap was wrapped onto sub-elements. Then 18-filament Nb3Sn plus 1 copper core restack billet was successfully drawn down and extruded into round wire as thin as a diameter of 0.84 mm. The longitudinal and cross-sectional images revealed most of barriers were continuous and intact. However, further experiments are needed to optimize the process in order to keep the all barriers continuous and intact after manufacturing.