Improvement of I/sub c/ in Nb/sub 3/Sn conductors by reduction of axial prestrain

Nb/sub 3/Sn conductors for large scale applications consisting of a high volume fraction of structural material which degrades I/sub c/ drastically because of the compressive prestrain on the Nb/sub 3/Sn filaments. This results from the higher thermal contraction of the structural components in comparison to that of Nb/sub 3/Sn during cooling from reaction to operation temperature. For example, in Nb/sub 3/Sn "Cable in Conduit" conductors using steel conduits I/sub c/ decreases by about 50% relative to the peak value at 12 T. Several alternatives for the reduction of the prestrain are possible leading to a remarkable improvement of I/sub c/: prestraining of the reacted conductor at room temperature; attaching the structural components onto the Nb/sub 3/Sn cable after reaction heat treatment of the cable; using reinforcing materials with lower thermal contraction coefficient comparable with that of Nb/sub 3/Sn.<>