Mechanical properties of Nb-Ti composite superconducting wires were tested at
room temperature. The results were analysed using simple composite theory, the rule
of mixtures. The objective is to predict the mechanical properties of Nb-Ti
superconducting composite wires as a function of volume ratio and geometry of the
components, the composite wire size and the effect of heat treatment at final drawing
wire sizes. To understand the mechanical behaviors of the Nb-Ti composite,
mechanical testing of the individual composite components, Nb-Ti filament and copper
matrix, was performed, and the geometry of the composite was also studied. The
results indicate that for the monofilamentary composite simple composite theory with
two components, Nb-Ti filament and copper matrix, can be used as the prediction of
the UTS of the composite. For the multifilamentary composite three components make
up the composites; a high strength Nb-Ti fiber, a low strength, high ductility bulk
copper matrix and a mid-strength (between the Nb-Ti fiber's and bulk copper matrix's)
interfilamentary copper matrix. After heavy cold work the UTS of Nb-Ti filaments and
bulk copper matrix in the composite saturate, while the UTS of the interfilamentary
copper increases as the interfilamentary spacing decreases. The UTS of the
interfilamentary copper matrix as a linear function of the reciprocal of interfilamentary
spacing is found. The controlling parameters in the manufacturing which determine the
mechanical properties of Nb-Ti composite superconducting wires include
superconductor to composite ratio, UTS of the Nb-Ti filament and copper matrix, wire
final drawing size, and geometry of the composite such as size and number of the
filaments, interfilamentary spacing, volume fraction of fringe and core bulk copper in
multifilamentary composites. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37677 |
| Date | 15 March 1991 |
| Creators | Liu, He |
| Contributors | Warnes, William H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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