The transport critical current density increased from 2610 to 5200 A/mm2at 5 T, 4.2 K, when a round monofilament Nb 47 wt.thinsp;percnt; Ti composite was rolled to an aspect ratio of 9.7 and was tested with the broad face of the tape parallel to the field. This value exceeds the previous maximum of 3700 A/mm2by about 50percnt;. Transmission electron micrographs show that more than 90percnt; of the agr;hyphen;Ti precipitates in the optimumhyphen;rolled filament are aligned within 10deg; of the broad face of the tape, whereas the precipitates had a random azimuthal orientation prior to rolling. The strong alignment caused the elementary pinning force to be greatly enhanced in the parallelhyphen;field orientation; however, in the orthogonal orientation theJcfell to low values characteristic of conventional wires having no agr;hyphen;Ti flux pinning centers.
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