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Microstructure of Nb/sub 3/ (AlSiB) supercondcuting tapes with extremely high critical current densities

Journal Article · · J. Mat. Res.; (United States)
OSTI ID:5833892
Alloys of Nb/sub 73/Al/sub 12/Si/sub 14.5/B/sub 0.5/ were rapidly solidified into amorphous ribbons using the melt spinning technique. These were isothermally annealed at temperatures ranging from 660 to 780 /degree/C. The A15 phase began to crystalline at 700 /degree/C and small amounts of second phases appeared at the higher temperatures. Crystallization was dependent on quenching rate as well as annealing conditions. Below 750 /degree/C nucleation was nonuniform and was enhanced by surfaces and quenched-in nuclei. Above 750 /degree/C nucleation became more uniform and completely crystalline ribbons with equiaxed grains /similar to/30 nm in diameter were obtained. These ultra fine grained ribbons had extremely high superconducting critical current densities of 8/times/10/sup 10/ A/m/sup 2/ and 5/times/10/sup 10/ A/m/sup 2/ at magnetic fields of 0.5 and 15 tesla, respectively, at 4.2 K.
Research Organization:
Department of Mechanical Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (US); Department of Metallurgy, University of Connecticut, Storrs, Connecticut 06268
OSTI ID:
5833892
Journal Information:
J. Mat. Res.; (United States), Journal Name: J. Mat. Res.; (United States) Vol. 4:3; ISSN JMREE
Country of Publication:
United States
Language:
English