Effects of Element Addition Into Cu Matrix for IT-Processed Ndb 3 Sn Wires

Element addition into Cu matrix in the internal tin (IT) process brings about diverse interesting diffusion reaction behavior in Nb 3 Sn layer formation. Zn is one of the attractive additives, which could enhance the growth rate of the Nb 3 Sn layer. In this paper, Ge, Ga, and Mg additions to the matrix are newly tried in IT process and some features of diffusion behavior are reported. Ge addition forms a Ge-rich layer around the Nb 3 Sn filaments, which might contribute to mechanical strengthening and/or increase of electric interface resistance. Ga can diffuse into the Nb 3 Sn layer, leading to slight enhancement of the critical magnetic field, but significant grain coarsening. Mg addition makes the grain morphology finer. Simultaneous addition of Zn and a small amount of Ge led to slight enhancement of high field $J_{{\text{c}}}$ .