New processing technique for forming flexible A-15 superconducting tapes with extremely high critical current densities

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6738025

Shi, D

A-15 compounds are extremely brittle and difficult to process for practical applications. A novel processing technique was developed to greatly improve the mechanical and superconducting properties of A-15 alloys. The new processing technique can be described as follows: (1) to select compounds that can form the A-15 phase (the selected A-15 compounds in this research were Ti3Nb6Mo3Si4 and Nb99.5-(x + y)AlxSiyB0.5 alloys); (2) to rapidly solidify them into the amorphous state; (3) to anneal the quenched amorphous products into ultra fine-grained single A-15 phase. The extreme grain refinement greatly improved the flexibility and the critical current density of the alloys. The melt spinning technique was used to rapidly solidify Ti3Nb6Mo3Si4 and Nb99.5-(x + y)AlxSiyB0.5 alloys. Ti3Nb6Mo3Si4 alloys were relatively easily formed into the amorphous state. Nb3Al alloys required the addition of glass forming elements Si and B. It was found that, without boron, the minimum amount of silicon that was required to form an amorphous ribbon was 18at%. It was also found that only 0.5at% boron greatly enhanced the glass forming tendency. The addition of boron reduced the necessary amount of silicon to 12at%. The annealed A-15 structures exhibited high flexibility in comparison with the A-15 structures obtained by quenching directly into the crystalline state.

• Research Organization: Massachusetts Univ., Amherst (USA)
• OSTI ID: 6738025
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
AMORPHOUS STATE
BETA-W LATTICES
CRITICAL CURRENT
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
FABRICATION
FLEXIBILITY
GRAIN REFINEMENT
MECHANICAL PROPERTIES
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
PHYSICAL PROPERTIES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TENSILE PROPERTIES
TITANIUM ALLOYS
TITANIUM BASE ALLOYS