The thermal expansion of several materials for superconducting magnets

The thermal expansion of several materials used in the construction of high field superconducting magnets has been measured from 4 K to room temperature. The materials were a NbTi and two Al5 multifilamentary conductors and several nonmetallic composites made from linen/phenolic, fiberglass/epoxy and superconducting wire/epoxy. The conductor expansions are typical of metals and the composite expansions are highly anisotropic. Both graphic and tabular values are provided by a computer fitting of the experimental data. The importance of thermal expansion differences in critical current measurement apparatus and superconducting magnet design are discussed.