Characterization of Nb-Ti superconductors with artificial pinning structures

Conference · Fri Jun 01 04:00:00 EDT 1990

OSTI ID:5196025

Dietderich, D R; Scanlan, R M

A series of multifilamentary APC Nb-Ti superconductors have been made with Nb added as a normal second phase to provide flux pinning centers. Two compositions, 12.5% vol % and 25 vol % Nb in Nb-Ti, have fabricated into multifilamentary composites using two different fabrication methods. One method used hot isostatic compaction and hot extrusion thoughout the processing. The other method (bundle-and-draw process) discontinued all hot processing at an intermediate level. While the J{sub c} values of the bundle-and-draw wires are quite promising, the critical current of the extruded wires appears to be limited by poor uniformity of the filament cross-sectional area along the conductor length. The large values of the index of the resistive transition and small filament standard-deviation-to-average area ratios observed in the wires produced by the bundle-and-draw process suggest extrinsic factors have little effect on J{sub c}. The variation in J{sub c} as the wire diameter is reduced appears to be most strongly affected by intrinsic factors: Nb distribution and pinning strength. The final filament microstructure and Nb spacing are shown to be difficult to calculate, e.g., the mean Nb spacing near the final wire size may be {1/2} to 1/3 that of the calculated value. 5 refs., 5 figs.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5196025
• Report Number(s): LBL-30063; SC-MAG--322; CONF-910635--16; ON: DE92000862
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
426001 -- Engineering-- Superconducting Devices & Circuits-- (1990-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
ELECTRON MICROSCOPY
MICROSCOPY
MICROSTRUCTURE
NIOBIUM ALLOYS
SUPERCONDUCTING WIRES
TITANIUM ALLOYS
WIRES