Stress Effects on W/Cu Reinforced Nb3Sn Composite Conductors

Filamentary Nb3Sn wire has become increasingly important as a high-field conductor because of its high upper critical field and critical temperature, in developing large scale magnets such as those used in a fusion reactor, energy storage and electrical machinery. Compound Nb3Sn, however, has a disadvantage in that superconducting properties of Nb3Sn are rapidly degraded by tensile and bend stresses1,2,3 resulting from reeling and coiling the material and, by electromagnetic force generated when a coil is energized and by thermal contraction stresses due to cooling.