The morphological development of the Nb sub 3 Sn phase in multifilamentary superconducting wire
Multifilamentary superconducting wire is used to produce high magnetic fields. One of the materials utilized is Nb{sub 3}Sn produced by bronze-type processes. To achieve peak properties the wire-fabrication technique and the Nb{sub 3}Sn grain morphology and composition must be optimized. This work investigated the variation in critical current of an internal-tin-processed wire and a bronze-processed wire to determine the source of the superior properties in the internal-tin wire. The internal-tin process was found to have a much higher J{sub c} at low fields, {approximately} 10T, than that produced in the bronze process. It was determined that either a temperature ramp or a multi-step heat treatment with distinct temperature steps could produce a high J{sub c}. Both heat treatments incorporate the low-temperature to high-temperature schedule which gives good critical-current properties due to its influence on the Nb{sub 3}Sn microstructure, stoichiometry, and state of atomic order. Two factors, reduced filament modulation and the increased amount of small equiaxed grains, are the primary sources of the superior properties. The upper critical field of the internal tin wire is lower than that produced in the bronze process. The lower H{sub c2} can have two origins, different strain states in the two wires or Nb{sub 3}Sn composition.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 5169746
- Country of Publication:
- United States
- Language:
- English
Similar Records
Critical current density and microstructural state of an internal tin multifilamentary superconducting wire
The critical current density and microstructural state of an internal tin multifilamentary superconducting wire
Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
CRITICAL CURRENT
CRITICAL FIELD
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
FABRICATION
GRAIN ORIENTATION
HEAT TREATMENTS
MAGNETIC FIELDS
MICROSTRUCTURE
MORPHOLOGY
NIOBIUM ALLOYS
ORIENTATION
SUPERCONDUCTING DEVICES
TIN ALLOYS