METHODS OF PRODUCING DUCTILE SUPERCONDUCTIVE ALLOYS

摘要

1473334 Superconductors BATTELLEINSTITUT eV 18 Sept 1974 [21 Sept 1973] 40710/74 Heading H1A [Also in Division C7] A method of producing a ductile superconductive alloy comprises forming a melt of constituents which combine to form a superconductive compound having the #-W(A15) structure and base metal and solidifying by cooling at a rate of at least 1000‹ C. per second, preferably 5 Î 104 to 1 x 106 ‹C. per second. The fast cooling rate achieves such a state of dispersion of the superconductive compound that the critical distance for the tunnel effect is not attained. It is stated that alloys containing less superconductive compound than is usually required may be made by the method, and also that superconductive alloys may be prepared from intermetallic compounds, e.g. V 3 Al, not usually exhibiting superconductive properties. Cooling at the required rate may be effected by dispersion into an argon atmosphere, optionally on to cooled plates. The granules obtained are compacted and extruded, cast or rolled, with soft-annealing, into desired shapes. Alloy systems specified have copper, silver or gold as the base metal and intermetallic compounds of niobium or vanadium with tin, aluminium, silicon, gallium or germanium as the superconductive compound. The proportions of alloy constituents are selected to correspond to the quasi-binary section of the ternary system. In the case of the gold-vanadium-silicon system, the alloy is clad with gold before rolling.