Influence of Axial Strain and Transverse Compressive Load on Critical Current of Nb3Sn Wires for the FCC

Nb
₃
Sn superconducting wires are under consideration for producing high field accelerator magnets for the proposed Future Circular Collider (FCC) due to their high critical field. R&D studies are ongoing worldwide with a target non-Cu critical current density (
J_c
) of 1500 A/mm
²
at 4.2 K, 16 T. As an accomplishment of this R&D, one of the conductor manufacturers, JASTEC, has developed Nb
₃
Sn wires with non-Cu
J_c
higher than 1100 A/mm
²
at 16 T, 4.2 K by a distributed-tin (DT) method. In high field Nb
₃
Sn magnets, degradation of performance has been frequently reported due to the brittleness of Nb
₃
Sn and the high electromagnetic force. To realize more robust Nb
₃
Sn accelerator magnets, electro-mechanical properties of the conductors should be deeply understood. In this study, the variation of the critical current with mechanical loading is evaluated for a DT Nb
₃
Sn wire in two configurations, i.e., under axial strain and under transverse compression.