Selected Composites for High Field Magnets

Abstract

AbstractThe national high magnetic field laboratory builds and uses various high field magnets for fundamental research. In building high field magnets, a variety of high strength composites are required because of the Lorentz stresses generated by high field exceeding the strength of most of the materials, particular conductors. For example, a field of 60 T can generate a magnetic pressure that corresponds to a stress in the conductor of 1.5 GPa, which is at the limit of known conducting materials with conductivity higher than 70% International Annealed Copper Standard and sizes suitable for building high field magnets. The design of high field magnets is limited by these forces and, consequently, by the available materials. At the same time, the materials need to have excellent physical properties. For instance, the conductors need to have high electrical conductivity and high specific heat and the superconductors should have high critical current in field and low alternative current losses. This paper outlines our requirements and research on metal matrix composite materials for building high field magnets. The discussions include both the macrocomposite and microcomposite. The scales of the structures in the composites are from millimeters to nanometers.