EFFECTS OF MAGNESIUM ADDITION TO THE CU-SN MATRIX IN THE COMPOSITE-PROCESSED NB3SN SUPERCONDUCTOR

The effects of the addition of a small amount of magnesium to the CuSn matrix in the composite-processed (bronze-processed) Nb3Sn super-conductor were investigated. It was found that the magnesium addition significantly suppresses the Nb3Sn grain coarsening. The fine Nb3Sn grain structure produced in the Nb/CuSnMg composite enhances the grain boundary diffusion of tin and consequently makes the Nb3Sn growth rate nearly twice as much as that of the Nb/CuSn composite. The significant increase in superconducting critical current attained in the Nb/CuSnMg composite shows that the magnesium addition is promising for the improvement of the current-carrying capacities of multifilamentary Nb3Sn superconductors. © 1979.