Composite core Nb/sub 3/Sn wires
Powdermetallurgically processed composite core Nb/sub 3/Sn wires, a new type of wires with filaments containing controlled amounts of normal conducting inclusions elongated in the wire axis, e.g. Ta or NbTi, have recently been developed in the authors lab. Composite cores replace the Nb cores which are inserted either in a CuSn or in a Cu matrix for producing wires by the bronze route or by the Internal Sn Diffusion process, respectively. The ductile inclusions are deformed during the wire drawing process to long ribbons being < 100 nm apart. If the reaction temperature is sufficiently low, the included Ta or NbTi show little reaction with the Nb/sub 3/Sn phase, but reduce the A15 grain growth in radial direction. The resulting enhanced pinning at the grain boundaries (artificial pinning) leads to higher critical current densities, particularly in the field range B < 14 T. For Ta inclusions, highest values of 5.5 x 10/sup 5/ A/cm/sup 2/ were measured at 10 T in the A15 layer of 19 core wires, i.e. > 50% higher than for the corresponding binary wire. The NbTi inclusions lead rather to an enhancement of J/sub c/ at higher fields: at 20 T, J/sub c/ = 5 x 10/sup 4/ A/cm/sup 2/ were measured. The difference between the observed field dependence for Ta and NbTi inclusions in the present configuration is explained by different degrees of prestress. The achievement of higher J/sub c/ values at 10 -12 T may be advantageous for their application in fusion magnets. A scale-up to industrial scale by replacing the P/M processed cores by continuous composite cores is discussed.
- Research Organization:
- 9201499; 3005585
- OSTI ID:
- 6042472
- Report Number(s):
- CONF-880812-
- Journal Information:
- IEEE Trans. Magn.; (United States), Vol. 25:2; Conference: Applied superconductivity conference, San Francisco, CA, USA, 21 Aug 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
NIOBIUM BASE ALLOYS
PHASE STUDIES
SUPERCONDUCTING MAGNETS
DESIGN
SUPERCONDUCTING WIRES
MATRIX MATERIALS
TIN ALLOYS
CRITICAL CURRENT
CURRENT DENSITY
DIFFUSION BARRIERS
DISLOCATION PINNING
DUCTILITY
FABRICATION
GRAIN BOUNDARIES
MAGNETIC FIELDS
POWDER METALLURGY
TANTALUM
THERMONUCLEAR DEVICES
TITANIUM ALLOYS
ALLOYS
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTROMAGNETS
ELEMENTS
EQUIPMENT
MAGNETS
MATERIALS
MECHANICAL PROPERTIES
METALLURGY
METALS
MICROSTRUCTURE
NIOBIUM ALLOYS
SUPERCONDUCTING DEVICES
TENSILE PROPERTIES
TRANSITION ELEMENTS
WIRES
420201* - Engineering- Cryogenic Equipment & Devices
360102 - Metals & Alloys- Structure & Phase Studies
360104 - Metals & Alloys- Physical Properties
700202 - Fusion Power Plant Technology- Magnet Coils & Fields
656100 - Condensed Matter Physics- Superconductivity