Optimization of the High Field Critical Current Density in MF Nb sub 3 SN for Magnet Use

摘要

We here report new high field critical current measurements on 1 M Nb sub 3 Sn conductors together with some bend test data on a conductor to be used for a 15 tesla magnet system. The results show that zero stress J/sub c/ values of 280 A/mm exp 2 (measured over the bronze + Nb cross section) at 15 tesla are obtained. These high values have now been obtained for 3 different composites from 3 different sources, suggesting that it should now be possible to specify high J/sub c/ from filamentary Nb sub 3 Sn with some confidence. We have also made measurements of J/sub c/ under tensile stress in the field range 13 to 16 tesla obtaining values of over 500 A/mm exp 2 at 15 tesla, approximately twice as large as those obtained in zero stress measurements. We also report on some room temperature bend test measurements for which no degradation in J/sub c/ was observed until strains of at least 0.5 percent were reached. (ERA citation 04:019984)