Effects of differential thermal contraction between the matrix and the filaments in mono- and multifilamentary Nb/sub 3/Sn on the superconducting critical temperature
The strain on Nb/sub 3/Sn due to the differential thermal contraction between the matrix (Cu, bronze) and the filaments (Nb, Nb/sub 3/Sn, Ta) of a superconducting wire is known to decrease the superconducting critical temperature T/sub c/. In order to study the effects of heat treatment conditions and filament size on the degradation of T/sub c/ by the strain. T/sub c/ for monofilamentary wires ((Nb/sub 3/Sn and bronze in Ta) in Cu matrix, and (bronze in Nb tubings) in Cu matrix) were measured for heat-treating periods in of 1 to 120 h at 725/sup 0/C. Several observations were made regarding the effects on T/sub c/ of thermal contraction strains from various components of the conductors. The influence of a Cu matrix on T/sub c/ was small (approx. 0.2 K). When the bronze matrix was inside Nb tubing the degradation of T/sub c/ due to strains was substantially larger than when the Nb filaments were in a bronze. Wires with smaller filament diameters achieved a maximum T/sub c/ in shorter heat treatment times than those with larger filaments. These results are discussed in terms of the critical currents of these wires under applied tensile strains.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- DOE Contract Number:
- EY-76-C-02-0016
- OSTI ID:
- 5805317
- Report Number(s):
- BNL-26950; CONF-791102-83; TRN: 80-002550
- Resource Relation:
- Conference: 8. symposium on engineering problems of fusion research, San Francisco, CA, USA, 13 Nov 1979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SUPERCONDUCTING WIRES
PHYSICAL PROPERTIES
NIOBIUM ALLOYS
TIN ALLOYS
GALLIUM ALLOYS
VANADIUM ALLOYS
BRONZE
COPPER ALLOYS
TANTALUM ALLOYS
CRITICAL TEMPERATURE
FILAMENTS
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
STRAINS
SUPERCONDUCTIVITY
THERMAL EXPANSION
ALLOYS
COPPER BASE ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EXPANSION
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
WIRES
360104* - Metals & Alloys- Physical Properties
420201 - Engineering- Cryogenic Equipment & Devices