Effects of Element Addition Into Cu Matrix for IT-Processed Nb3Sn Wires

Abstract

Element addition into Cu matrix in the internal tin (IT) process brings about diverse interesting diffusion reaction behavior in Nb3Sn layer formation. Zn is one of the attractive additives, which could enhance the growth rate of the Nb3Sn 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 Nb3 Sn filaments, which might contribute to mechanical strengthening and/or increase of electric interface resistance. Ga can diffuse into the Nb3Sn 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 $J_{{\text{c}}}$ .