A15 superconductors through direct solid-state precipitation: V/sub 3/Ga and Nb/sub 3/Al

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5399020

Hong, M

A solid-state precipitation process was used to prepare superconducting tapes containing an A15 phase, V/sub 3/Ga or Nb/sub 3/Al, in a ductile niobium or vanadium containing BCC matrix. Ingots weighing as large as 30 approx. 50 gms of V-(14 approx. 19 at %) Ga and Nb-(13 approx. 22 at %) Al were prepared by arc-melting, homogenized, quenched, warm-rolled over 99% into tape, and aged at temperatureees in the range 600/sup 0/C to 1000/sup 0/C to precipitate the superconducting A15 phase. The features demonstrated by the process are very attractive for practical applications. In the V-Ga system, transmission electron microscopy (TEM) studies revealed the A15 precipitates in an elongated form. However for the Nb-Al samples, deformed and aged at 750/sup 0/C, TEM studies revealed A15 precipitation in fine equi-axed particles which formed as a semi-continuous network over sub-grain boundaries formed by the recovery of deformation-induced dislocations. In the V-Ga system, the maximum critical transition temperatur (approx. 15 K) was found in materials aged at temperatures of 750/sup 0/C or below. At these aging temperatures the T/sub c/ initially increased with aging time and passed through a distinct maximum.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5399020
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AGE HARDENING
ALLOYS
ALUMINIUM ALLOYS
ARC FURNACES
CHEMICAL PREPARATION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DEFORMATION
DISLOCATIONS
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRIC FURNACES
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
FURNACES
GALLIUM ALLOYS
GRAIN BOUNDARIES
HARDENING
HIGH TEMPERATURE
INFORMATION
INTERMETALLIC COMPOUNDS
LINE DEFECTS
MELTING
MICROSCOPY
MICROSTRUCTURE
MIXTURES
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
NUMERICAL DATA
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRECIPITATION
QUENCHING
SEPARATION PROCESSES
SOLID SOLUTIONS
SOLUTIONS
SUPERCONDUCTIVITY
SYNTHESIS
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
VANADIUM ALLOYS
VANADIUM BASE ALLOYS
VERY HIGH TEMPERATURE