The critical current density and microstructural state of an internal tin multifilamentary superconducting wire
The critical current density (J /SUB c/ ) of internal tin wires is increased when low-temperature diffusion heat treatments are performed prior to a high temperature reaction. To determine the variation of J /SUB c/ with prereaction heat treatments a copper-stabilized IGC internal tin wire with an outside diameter of 0.267mm was studied. The wire has 2 to 2.5 ..mu..m diameter filaments, and within the Ta barrier, the area ratio of the copper matrix and Sn core to Nb is about 2.2. Due to the character of the Cu-Sn phase diagram, heat treatments at a series of temperatures below the Nb/sub 3/Sn reaction temperature affect the local Sn concentration in the matrix about the Nb filaments. The variation in J /SUB c/ resulting from these heat treatments is a consequence of the microstructural state of the conductor and the morphology of the Nb/sub 3/Sn layer produced. The results of this work show that the internal tin and bronze-processed wires have different J /SUB c/ (H) characteristics. The two processes have comparable critical currents at high fields, suggesting the same H /SUB c2/ , while at low fields the internal tin wire is superior, suggesting a better grain morphology.
- Research Organization:
- Lawrence Berkeley Laboratory, and Department of Materials Science and Mineral Engineering, University of California, Berkeley, California
- OSTI ID:
- 6340094
- Report Number(s):
- CONF-840937-
- Journal Information:
- IEEE Trans. Magn.; (United States), Vol. MAG 21:2; Conference: Applied superconductivity conference, San Diego, CA, USA, 9 Sep 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
36 MATERIALS SCIENCE
SUPERCONDUCTING WIRES
CRITICAL CURRENT
CURRENT DENSITY
FABRICATION
FILAMENTS
MICROSTRUCTURE
BRONZE
COPPER ALLOYS
CRITICAL FIELD
HEAT TREATMENTS
MORPHOLOGY
NIOBIUM ALLOYS
SUPERCONDUCTIVITY
TANTALUM ALLOYS
THERMAL DIFFUSION
TIN ALLOYS
ALLOYS
COPPER BASE ALLOYS
CRYSTAL STRUCTURE
CURRENTS
DIFFUSION
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
MAGNETIC FIELDS
PHYSICAL PROPERTIES
WIRES
420201* - Engineering- Cryogenic Equipment & Devices
360104 - Metals & Alloys- Physical Properties