Nb3Sn conductors reinforced with dispersion-hardened copper (DHC) alloy

The axial strain characteristics of a group of three similar experimental Nb3Sn superconductor were measured over a broad range of magnetic fields. All three conductors were manufactured using the internal-tin process, and a dispersion-hardened-copper (DHC) reinforcement was used in each conductor for increased tensile strength. The first conductor has two concentric rings of stabilizing copper surrounding the noncopper core, which contains the internal tin. The inner ring is pure copper and the outer ring is DHC. The copper stabilizer makes up 72% of the conductor's total volume. Both of the other conductors have an internal-tin ring surrounding their cores and 56% external copper stabilizer. One of the conductors uses pure copper for the stabilizer and DHC for the core's matrix; the other conductor has the opposite configuration, a pure-copper matrix and DHC stabilizer. All three conductors have tantalum diffusion barriers between core and stabilizer. The conductor specifications are given in Tables 7 through 9. The Ic and Jc values are based on an electric field criterion (Ec) of 2 μV/cm