Abstract This invention provides a billet and a method for shaping the same for the production of composite superconductor wire composed of at least one high yield strength superconductor core surrounded by a low yield strength matrix material that is uniformly clad on and around and bonded to the core for use in magnets and the like. In one actual billet, which has a core to sleeve yield strength ratio of about 7-1, the billet has a coreto-sleeve diameter ratio of between about 0.4 and 0.9 and a nose cone semi-angle of 5* for extrusion through a die semi-angle of 5* for area reductions of 39 to 65 percent. This billet comprises an aluminum clad niobium-titanium core with ratios of core area to sleeve area ranging from 27.5 to 100.2 percent. The billet according to the method of this invention, is extruded without fabrication damage and/or annealing to produce a uniform bond between the superconductor core and the matrix.
The method of claim 1 in which before said extruding step the outside of said matrix material is smoothed and coated with a lubricant, and thereafter the extruding step is carried out sequentially in increments for providing a 90 percent total cross-sectional area reduction that forms a composite superconductor wire substantially without fabrication damage and with a uniform bond between said components at extrusion pressures of at least 25,000 psi without annealings between said increments.
Claim 2
Dependent Claim
76 words
The method of claim 1 in which said extruding step is performed according to a schedule for the incremental reduction in the cross-sectional area of said components, comprising an initial 47 to 65 percent cross-sectional area reduction, and at least one subsequent cross-sectional area reduction of between about 40 and 50 percent for achieving a total final cross-sectional area reduction of at least 90 percent in said components from their initial cross-section area in said billet.
Claim 3
Dependent Claim
185 words
A billet for producing a composite superconductor wire by extrusion, comprIsing: a. first means forming a right circular cylinder of Ti-56 percent Nb alloy in the shape of a rod having a longitudinal axis and an outside diameter of at least 0.116 inches; b. second means forming an annular, right circular, uniform diameter, Al sleeve around and concentric with said first means and having a longitudinally extending axis corresponding with the axis of said first means; said second means having a first end tapered in a semi-cone angle of 5* from the longitudinally extending axis thereof for insertion into a die for the co-extrusion of said first and second means, and c. Al cap means bonded with epoxy resin to the opposite end of said second means from said first end that is tapered; said first and second means having an initial first-to-second means diameter ratio between about 0.4 and 0.9 for preventing fabrication damage and providing plastic flow and a uniformly strong bond between said first and second means during extrusion of the same at high pressures to produce a composite superconductor wire therefrom.