Alloy Composition Optimization for High Critical Density of (Nb,Ta,Ti)3Sn Superconductor

The typical critical current density of best Nb3Sn superconducting composite is approximately 1600 A/mm2 at 15T and 4.2K. This density is achieved in RRP® strand with ternary alloy of either (Nb,Ti)3Sn or (Nb,Ta)3Sn. This objective of this study is to improve superconducting property of (Nb, Ta, Ti)3Sn to Jc >1800 A/mm2 at the same field and temperature by optimizing Ta and Ti composition in the final A15 compound layer. Previously conducted studies have sought whether Ti doping into (Nb, Ta)3Sn would enhance high magnetic field performance. Attempts were to control Ti content doped into Nb7.5wt%Ta starting alloy during heat treatment to form (Nb,Ta, Ti)3Sn. However, given the fact that the Nb7.5wt%Ta alloy is already very nearly optimally doped, this is not the best system for finding the proper Ti doping level. In this proposed study, we will use Nb1wt%Ta as the starting alloy and dope Ti into the alloy to improve superconducting performance over today¿s best achievement. High field superconducting magnet built with Nb3Sn is one of essential components in NMR and ICR spectrometers that are widely used in new drug discovery and biotechnology. Proton therapy for cancer treatment relies upon a compact cyclotron with such a magnet. Commercial Applications and other Benefits as described by the awardee Large science projects requiring high field magnets, such as hadron collider for high energy physics, magnetic fusion searching ever lasting energy source, and basic material behavior studies, also feature Nb3Sn as the chosen superconducting materials for the magnets. Enhanced performance of this material would not only improve the performances of these devices, but reduce their cost