Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Compressive Prestrain in High-Niobium-Fraction Nb3Sn Superconductors

Published

Author(s)

John (Jack) W. Ekin, Najib Cheggour, Mike Abrecht, Cameron C. Clickner, Michael Field, Seungok Hong, Jeffrey Parrell, Y. Zhang

Abstract

Multifilamentary Nb3Sn superconducting strands fabricated with high niobium fractions have exceptionally high critical-current densities but are sometimes marginally stable during testing. We report a technique for determining the pre-strain in such conductors, in which additional stabilizing copper is electroplated onto the conductor and the pre-strain is determined by extrapolation to the as-fabricated niobium fraction. This technique is used to measure the pre-strain in conductors with high niobium fractions of 20% to 30%. Values of the pre-strain, εmax in these conductors are reduced to the range 0.1% to 0.2%, which is significantly less than the εmax values of 0.2% to 0.4% in traditional bronze-process Nb3Sn conductors (where niobium fractions are typically about 10% to 15%). However, including about 20% dispersion-strengthened copper into the conductor matrix restores εmax to the range 0.25% to 0.35%, thus providing practical levels of εmax for magnet design in high-niobium-fraction strands.
Citation
IEEE Transactions on Applied Superconductivity
Volume
15
Issue
2

Keywords

axial strain, copper-alloy, critical current, niobium-tin, thermal contraction

Citation

Ekin, J. , Cheggour, N. , Abrecht, M. , Clickner, C. , Field, M. , Hong, S. , Parrell, J. and Zhang, Y. (2005), Compressive Prestrain in High-Niobium-Fraction Nb<sub>3</sub>Sn Superconductors, IEEE Transactions on Applied Superconductivity, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31825 (Accessed November 26, 2022)
Created May 31, 2005, Updated October 12, 2021