New Materials-The Road to Higher Magnetic Field Generation

Abstract

Economic advances in high field generation are strongly influenced by available materials. Incremental improvements of the conductor ultimate tensile strength (UTS), conductivity, strain tolerance, fatigue strength, etc. can result in remarkable benefits for producing higher fields. Conventional composites improve on specific properties governed by the rule of mixtures. Recently developed metal-metal-matrix microcomposites improve on the rule of mixtures. Such materials depend on the microgeometry of the composite and can approach the theoretical ultimate tensile strength of the conductor. An example is the recently manufactured Cu/Nb metal-metal-matrix microcomposite fabricated by conventional superconductor wire technologies. A pulsed magnet using such a conductor with an ultimate tensile strength (UTS) of about 145 ksi (1 GPa) and 70% conductivity of Cu at 300 K was used to produce 68.4T with 100 kJ in a 1.3 cm i.d. wire-wound pulsed magnet cooled to 77 K. Brief summaries are given of limits of insulation, superconductors and coolants.