METHOD OF FABRICATING AN ELONGATED ARTEFACT

A component (10) for making A15 Nb3Sn superconducting wire is of plane-filling cross-section after removing temporary additions (6, 7). It consists of a central pillar (1) of aluminium (later replaced by tin) surrounded by a two-deep array of polygonal copper columns 2/2a containing niobium rods. Many (e.g. 61) components (10) are voidlessly stacked together and extruded. The niobium rods adopt and retain a uniform distribution with minimum intervening material. This ''sixty-one'' member retains its shape during the extrusion and is itself of plane-filling cross-section. Several of them are voidlessly stacked together and on heat-treatment of the whole, the tin diffuses over a relatively short path and hence consistently into the rods, whereby there is formed a kilofilament Nb3Sn wire.