Further Studies of Nb3Sn Wire for the 45-T Hybrid Magnet
The 45-T Hybrid Magnet will use NbTi and Nb3Sn Cable-In-Conduit Conductors (CICC) operating at 10 kA to produce a field of 14-T on axis in a 710-mm diameter magnet bore. A candidate Nb3Sn wire has been evaluated and selected for this application. However, the copper stabilizer of some wires has been shown to be susceptible to contamination, from unknown sources, which results in low Residual Resistivity Ratios (RRR). Here we report a characterization of wire given abbreviated heat treatment schedules designed to improve the RRR. It is shown that the RRR is readily improved by modifying the heat treatment schedule while critical current density remains above specified minimums. RRR and critical current density as a function of heat treatment and critical current density as a function of axial strain are reported.
KeywordsCritical Current Density Heat Treatment Time High Critical Current Density Heat Treatment Schedule Residual Resistivity Ratio
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