68.4-T-long pulse magnet: Test of high strength microcomposite Cu/Nb conductor

A multilayer wire-wound pulsed field magnet was fabricated using a new metal-matrix microcomposite Cu/Nb conductor. The 0.5-in.-i.d. magnet used square cross-section Cu/Nb wire, precompressed in a hardened steel container and cooled to 77 K, to generate 68.4±1 T for a 5.6-ms half-period. The maximum field was generated using a 100-kJ, 4-kV capacitor bank of the Francis Bitter National Magnet Laboratory pulsed field facility. The Cu/Nb composite had an ultimate tensile strength of 180 ksi at 77 K and 140 ksi at 293 K. These new microcomposites have exceptional strength, electrical, and thermomechanical properties for very high stress applications.