Mechanical behavior and stress effects in hard superconductors [electronic resource] : a review

Published:: Washington, D.C. : United States. Dept. of Energy, 1977.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:: Pages: 72 : digital, PDF file
Additional Creators:: Oak Ridge National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

The mechanical properties of type II superconducting materials are reviewed as well as the effect of stress on the superconducting properties of these materials. The bcc alloys niobium-titanium and niobium-zirconium exhibit good strength and extensive ductility at room temperature. Mechanical tests on these alloys at 4.2/sup 0/K revealed serrated stress-strain curves, nonlinear elastic effects and reduced ductility. The nonlinear behavior is probably due to twinning and detwinning or a reversible stress-induced martensitic transformation. The brittle A-15 compound superconductors, such as Nb/sub 3/Sn and V/sub 3/Ga, exhibit unusual elastic properties and structural instabilities at cryogenic temperatures. Multifilamentary composites consisting of superconducting filaments in a normal metal matrix are generally used for superconducting devices. The mechanical properties of alloy and compound composites, tapes, as well as composites of niobium carbonitride chemically vapor deposited on high strength carbon fibers are presented. Hysteretic stress-strain behavior in the metal matrix composites produces significant heat generation, an effect which may lead to degradation in the performance of high field magnets. Measurements of the critical current density, J/sub c/, under stress in a magnetic field are reported. Modest stress-reversible degradation in J/sub c/ was observed in niobium-titanium composites, while more serious degradation was found in Nb/sub 3/Sn samples. The importance of mechanical behavior to device performance is discussed.

Report Numbers:

E 1.99:ornl/tm-5857
ornl/tm-5857

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Note:

Published through SciTech Connect.
11/01/1977.
"ornl/tm-5857"
Koch, C. C.; Easton, D. S.

Funding Information:

W-7405-ENG-26

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