Critical currents in liquid-quenched Nb/sub 3/Al

Journal Article · Wed Jun 01 04:00:00 EDT 1977 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.323981· OSTI ID:7113078

Lo, K; Bevk, J; Turnbull, D

Critical current densities of over 1.8 x 10/sup 6/ A/cm/sup 2/ at 4.2 degreeK and 150 kG have been achieved in Nb/sub 3/Al tapes rapidly quenched from the liquid state at rates of 10/sup 5/--10/sup 6/ degreeC/sec. The superconducting transition temperature is about 16 degreeK, indicating a relatively high degree of order, and increases to 18.4 degreeK upon annealing at 750 degreeC. The observed microstructure depends sensitively on the quenching rate and consists of small submicron grains surrounded by a thin boundary layer of different composition. The grain size is roughly inversely proportional to the temperature gradient during quenching. The quoted critical current densities, the highest observed to date in any superconductor, should be regarded as a lower limit of the material critical value imposed by the heating problems due to the contact resistance.

• Research Organization: Division of Engineering and Applied Physics, Harvard University, Cambridge, Massachusetts 02138
• OSTI ID: 7113078
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 48:6; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
ALUMINIUM ALLOYS
ANNEALING
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
GRAIN SIZE
HEAT TREATMENTS
HEATING
MICROSTRUCTURE
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
PHYSICAL PROPERTIES
QUENCHING
SIZE
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE GRADIENTS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
TYPE-II SUPERCONDUCTORS