Method of fabricating multifilament intermetallic superconductor

Claim 1

A method of making a superconducting wire of the type in which a predetermined number of fine filaments of intermetallic superconductor having the composition A 3 B and the A-15 crystal structure are embedded in a matrix of normal conductor which comprises distributing wires of A having a nominal diameter not greater than 0.050 inch in a body consisting of Cu and interspersed B material, the B material being provided as a coating on Cu stock having a cross sectional dimension in one direction not greater than the diameter of the wires of A, mechanically working the composite to reduce its cross section to the desired final wire diameter with concomitant elongation, and heating treating the conductor to cause the dispersed B material to diffuse into the Cu and to migrate to and react with the A material filaments to form filaments of A 3 B.

Claim 2

A method of making a superconducting wire of the type in which a predetermined number of fine filaments of intermetallic superconductor having the composition A 3 B and the A-15 crystal structure are embedded in a matrix of normal conductor which comprises distributing wires of A having a nominal diameter not greater than 0.050 inch in a body consisting of Cu and interspersed B material, the B material being provided as a coating on Cu stock having a cross sectional dimension in one direction not greater than the diameter of the wires of A, mechanically working the composite to reduce its cross section to the desired final wire diameter with concomitant elongation, and heating treating the conductor to cause the dispersed B material to diffuse into the Cu and to migrate to and react with the A material filaments to form filaments of A 3 B.

Claim 5

A method of fabricating a multifilament Nb 3 Sn superconducting wire having a predetermined number of Nb 3 Sn filaments distributed in a matrix of normally conducting metal which comprises (a) assembling a composite of said predetermined number of Nb wires having a nominal diameter not greater than 0.050 inch, Cu and Sn, the Sn being in the form of an adhered coating on the Cu, the Cu being in a form having one cross sectional dimension not exceeding the diameter of the Nb wires and the Sn coating being of a thickness to provide Sn in an amount of 10% to 25% of the weight of Cu and the Cu+Sn being in an amount to provide from 1 to 4 times the Nb content by volume, (b) mechanically working said composite to reduce its cross section to the desired final wire diameter with concomitant elongation, and (c) heat treating the conductor to cause the dispersed Sn to diffuse into the Cu and to migrate to and react with the Nb filaments to form filaments of Nb 3 Sn.

Claim 6

A method of fabricating a multifilament Nb 3 Sn superconducting wire having a predetermined number of Nb 3 Sn filaments distributed in a matrix of normally conducting metal which comprises (a) assembling a composite of said predetermined number of Nb wires having a nominal diameter not greater than 0.050 inch, Cu and Sn, the Sn being in the form of an adhered coating on the Cu, the Cu being in a form having one cross sectional dimension not exceeding the diameter of the Nb wires and the Sn coating being of a thickness to provide Sn in an amount of 10% to 25% of the weight of Cu and the Cu+Sn being in an amount to provide from 1 to 4 times the Nb content by volume, (b) mechanically working said composite to reduce its cross section to the desired final wire diameter with concomitant elongation, and (c) heat treating the conductor to cause the dispersed Sn to diffuse into the Cu and to migrate to and react with the Nb filaments to form filaments of Nb 3 Sn.

Claim 7

A method for the fabrication of a multifilament Nb 3 Sn superconducting wire which comprises (a) crimping Cu foil strip having a thickness no greater than the diameter of the Nb wires referred to below to form corrugations therein, (b) Sn plating the corrugated foil strip, (c) inserting Nb wires having a nominal diameter not greater than 0.050 inch into the corrugations of the Sn plated corrugated foil strip, (d) rolling the Sn plated corrugated Cu strip containing the Nb wires into a spiral, (e) mechanically working the said spiral to reduce its diameter to that of the desired superconducting wire and to concomitantly consolidate and elongate it, and (f) heat treating the product of step (e) to cause the Sn to diffuse through the structure and form Nb 3 Sn at the surface of each Nb filament.

Claim 8

A method for the fabrication of a multifilament Nb 3 Sn superconducting wire which comprises (a) crimping Cu foil strip having a thickness no greater than the diameter of the Nb wires referred to below to form corrugations therein, (b) Sn plating the corrugated foil strip, (c) inserting Nb wires having a nominal diameter not greater than 0.050 inch into the corrugations of the Sn plated corrugated foil strip, (d) rolling the Sn plated corrugated Cu strip containing the Nb wires into a spiral, (e) mechanically working the said spiral to reduce its diameter to that of the desired superconducting wire and to concomitantly consolidate and elongate it, and (f) heat treating the product of step (e) to cause the Sn to diffuse through the structure and form Nb 3 Sn at the surface of each Nb filament.

Claim 9

A method for the fabrication of a multifilament Nb 3 Sn superconducting wire which comprises (a) cabling together Nb wires having a nominal diameter not greater than 0.050 inch and Sn plated Cu wires having a cross-sectional dimension in one direction not greater than the diameter of the Nb wires to provide a volumetric ratio of (Sn+Cu)/Nb in the range from 1 to 4, (b) compacting said cable to reduce the voids therein and to form the external surface to adapt it to combine with other like cables to form a bundle of such cables, (c) combining said cable with a plurality of like cables to form a bundle of such cables, (d) mechanically working said bundle of cables to reduce its cross section to that of the desired superconducting wire and to concomitantly consolidate and elongate it, and (e) heat treating the product of step (d) to cause the Sn to diffuse through the structure and form Nb 3 Sn at the surface of each Nb filament.

Claim 10

A method for the fabrication of a multifilament Nb 3 Sn superconducting wire which comprises (a) cabling together Nb wires having a nominal diameter not greater than 0.050 inch and Sn plated Cu wires having a cross-sectional dimension in one direction not greater than the diameter of the Nb wires to provide a volumetric ratio of (Sn+Cu)/Nb in the range from 1 to 4, (b) compacting said cable to reduce the voids therein and to form the external surface to adapt it to combine with other like cables to form a bundle of such cables, (c) combining said cable with a plurality of like cables to form a bundle of such cables, (d) mechanically working said bundle of cables to reduce its cross section to that of the desired superconducting wire and to concomitantly consolidate and elongate it, and (e) heat treating the product of step (d) to cause the Sn to diffuse through the structure and form Nb 3 Sn at the surface of each Nb filament.