The influence of bending strain on the critical current of Nb

Valentina Corato, Luigi Muzzi, Antonio Della Corte, Aldo Di Zenobio, Simonetta Turtú, Rosario Viola

Research output: Contribution to journalArticle

Abstract

The effect of bending strain on the transport properties of Nb3Sn strands has been the object of several investigations in the last years. We report on the performances of internal tin Nb3Sn strands with different filament twist pitches, pre-com- pressed by swaging into thin stainless steel tubes before the reaction heat treatment and subject to pure bending strain. We have previously reported on the comparison between the performances of the technological OST-Dipole strand (TW-strand) with those of the same strand, but with untwisted superconducting filaments (UNTW-strand). The critical current, as well as the n-index of the samples with twisted filaments gradually degraded with the applied bending strain, while an enhancement of the performances has been observed on UNTW-strands. Here, results on further experimental measurements carried out on OKSC internal tin strands with different filament twist pitches are discussed, in order to clarify some aspects of the current transfer process within the strands. Finally, we carried out an analysis through the second derivative of the V-I curve, which evidenced a peaked critical current distribution for the UNTW-strands, while TW-strands under bending showed a higher degree of non-homogeneity, proven by broader distributions. © 2009 IEEE.
Original languageEnglish
Article number5067085
Pages (from-to)2624 - 2627
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume19
Issue number3
DOIs
Publication statusPublished - Jun 2009
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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