Microstructure and Superconducting Properties of Brass Matrix Internal Tin Nb$_3$Sn Wire With Ti Doping to Nb Core

Nb
₃
Sn superconducting wires are widely used for high field applications. It is also expected to play a vital role for high field application in the future, such as future circular collider (FCC). Further improvement in Jc performance is required to realize FCC. We have been studying the effect of element addition into Cu matrix in the internal tin (IT) processed Nb
₃
Sn conductor. In our previous brass method IT wire, where Ti is doped to central Sn cores, Ti is accumulated between the sub-elements and is inhomogeneously distributed across the wire after the heat treatment. To solve this problem, we tried Ti doping to Nb cores on the brass matrix IT wire. We prepared the specimens using Nb-0, 1, 1.54 at%Ti rod as Nb core. Nb
₃
Sn grain morphology and diffusion reaction behavior of these specimens were compared and we investigated the correlation between the microstructure and the superconducting properties on the specimens with Ti doping to Nb cores.