The role of oxygen and zirconium in the formation and growth of Nb[sub 3]Sn grains

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

OSTI ID:5188500

Rumaner, L E ^[1]; Benz, M G; Hall, E L ^[2]

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1. Univ. of Washington, Seattle, WA (United States)
2. GE Corporate Research and Development, Schenectady, NY (United States)

One method of producing Nb[sub 3]Sn is to react a molten tin alloy with a solid niobium alloy. Using this process, the addition of zirconium and oxygen to the niobium foil has been found to dramatically reduce the Nb[sub 3]Sn grain size and affect the Nb[sub 3]Sn superconducting critical current properties. Nb[sub 3]Sn grains grow semicoherently on the niobium alloy foil. The initial grain size is about 50 nm. These initial Nb[sub 3]Sn grains coarsen rapidly to become equiaxed grains about 0.2 [mu]m in diameter. The equiaxed Nb[sub 3]Sn grains away from the Nb/Nb[sub 3]Sn interface are completely surrounded by a tin alloy phase that would have been liquid at the reaction temperature. Based on transmission electron microscopy observation and electrical property characterization, it is concluded that ZrO[sub 2] clusters, less than 10 [angstrom] in size, form in the niobium alloy foil during processing. These clusters combine at the Nb/Nb[sub 3]Sn interface to form ZrO[sub 2] precipitates. The ZrO[sub 2] precipitates are found in all of the Nb[sub 3]Sn grains that have formed from a reaction between the liquid tin and the solid niobium at the Nb/Nb[sub 3]Sn interface. The precipitates are coherent with their host Nb[sub 3]Sn grains. During Nb[sub 3]Sn grain growth, the ZrO[sub 2] precipitates dissolve in shrinking grains and reprecipitate in growing grains, as the migrating grain boundary intersects the precipitate. This dissolution/reprecipitation process slows the growth of Nb[sub 3]Sn grains.

• OSTI ID: 5188500
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 25:1; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
CHALCOGENIDES
DATA
ELEMENTS
EXPERIMENTAL DATA
GRAIN GROWTH
INFORMATION
INTERMETALLIC COMPOUNDS
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
NIOBIUM ALLOYS
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN ADDITIONS
OXYGEN COMPOUNDS
TIN ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ZIRCONIUM
ZIRCONIUM ADDITIONS
ZIRCONIUM ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES