Method of production multifilamentary intermetallic superconductors

Claim 1

In the method of manufacturing a composite multi-filamentary superconductor of the type A 3 B where A is selected from the group consisting of Nb and V, and B is selected from the group consisting of Sn and Ga by (a) forming a composite billet having a plurality of filaments of A embedded in a matrix of Cu and having a source of B external to the Cu matrix, (b) extruding said composite billet to reduce its cross sectional area and increase its length, (c) wire drawing the extruded product to the final conductor cross sectional area, and (d) heat treating the so reduced conductor to cause the B material to diffuse into and through the Cu and react with the filaments of A to form A 3 B, the improvement which comprises providing the B material external to the Cu matrix in the preextrusion billet in the form of surrounding concentric uniform thickness annual layers of B surrounded by concentric annular layers of Cu, the thickness of B being approximately, but not exceeding, 0.50 mm per layer, and providing a plurality of such layers of B material and Cu, the number of such layers being determined by the total amount of B material required to react with the available A material to form A 3 B.