Current-Carrying Capacity and Energy Losses in Hydrostatically Extruded NbTi Wires

Manufacturing superconducting composite wires with filament diameters of the order of the coherence length ξ seems to be of practical importance for two reasons: it results in increased current-carrying capacity and considerably less energy loss with changes in transport current and external magnetic field. Composite conductors with such fine filaments have not yet been made successfully by conventional commercial processing techniques (i.e., wire drawing). Hydroextrusion solves this problem: Multistage assemblies and coextrusion of superconductor and normal metal matrix by high-pressure fluid make it possible to produce a multifilamentary superconductor comprised of practically any number of ultrafine filaments.