Effects of differential thermal contraction between the matrix and the filaments in mono- and multifilamentary Nb/sub 3/Sn on the superconducting critical temperature

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5805317

Aihara, K; Suenage, M; Luhman, T

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
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
420201 -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
BRONZE
COPPER ALLOYS
COPPER BASE ALLOYS
CRITICAL TEMPERATURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EXPANSION
FILAMENTS
GALLIUM ALLOYS
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
NIOBIUM ALLOYS
PHYSICAL PROPERTIES
STRAINS
SUPERCONDUCTING WIRES
SUPERCONDUCTIVITY
TANTALUM ALLOYS
THERMAL EXPANSION
THERMODYNAMIC PROPERTIES
TIN ALLOYS
TRANSITION TEMPERATURE
VANADIUM ALLOYS
WIRES