Characterization of Nb-Al superconducting material
The superconducting A15 phase formation in the Nb/Al binary system was studied in order to provide a systematic approach toward achieving optimum processing conditions for Nb/Al superconducting wires. A series of Nb/Al multi-layered thin-film samples was made to simulate reactions in powder metallurgy (P/M) processed wires while a Nb-Al bulk sample was made by an arc-welding technique to study reactions in the bulk. It was found that the reactions in P/M wires and multi-layered thin-film samples were governed by kinetics while those in the bulk sample were governed by thermodynamics. The optimum Al/Nb layer configuration to avoid remaining Nb or Nb/sub 2/Al was qualitatively calculated to be 1100/angstrom/ /approximately/ 1260/angstrom/ for Nb and 290/angstrom/ /approximately/ 330/angstrom/ for Al. The average Nb filament thickness and the critical current densities of various superconducting wires showed good correlation in spite of the differences in processing and the microstructural inhomogeneity. It was shown that the critical current density of a superconducting wire increased by improving its Nb/Al filament distribution. It is concluded that the critical current density of a Nb/Al superconducting wire can be maximized if Nb and Al filaments are reduced to the optimum thickness range and homogeneously distributed. 118 refs., 48 figs., 3 tabs.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6230992
- Report Number(s):
- LBL-26381; ON: DE89008296
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102 -- Metals & Alloys-- Structure & Phase Studies
360104* -- Metals & Alloys-- Physical Properties
ALLOY SYSTEMS
ALLOYS
ALUMINIUM ALLOYS
BINARY ALLOY SYSTEMS
COHERENT SCATTERING
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENT DENSITY
CURRENTS
DIFFRACTION
DIFFUSION
DIMENSIONS
ELECTRIC CURRENTS
ELECTRON MICROSCOPY
FILMS
INTERMETALLIC COMPOUNDS
LATTICE PARAMETERS
METALLURGY
MICROSCOPY
MICROSTRUCTURE
NIOBIUM ALLOYS
POWDER METALLURGY
SAMPLE PREPARATION
SCATTERING
SUPERCONDUCTING FILMS
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION