Tensile testing method for rare earth based bulk superconductors at liquid nitrogen temperature

K. Kasaba, K. Katagiri, A. Murakami, G. Sato, T. Sato, M. Murakami, N. Sakai, H. Teshima, M. Sawamura

Research output: Contribution to journalConference article

4 Citations (Scopus)

Abstract

Bending tests have been commonly carried out to investigate the mechanical properties of melt-processed rare earth based bulk superconductors. Tensile tests by using small specimen, however, are preferable to evaluate the detailed distribution of the mechanical properties and the intrinsic elastic modulus because no stress distributions exist in the cross-section. In this study, the tensile test method at low temperature by using specimens with the dimensions of 3 × 3 × 4 mm from Y123 and Gd123 bulks was examined. They were glued to Al alloy rods at 400 K by using epoxy resin. Tests were carried out at liquid nitrogen temperature (LNT) by using the immersion type jig. Although the bending strength in the direction perpendicular to the c-axis of the bulks at LNT is higher than that at room temperature (RT), the tensile strength at LNT was lower than that at RT. Many of specimens fractured near the interface between the specimen and the Al alloy rod at LNT. According to the finite element method analysis, it was shown that there was a peak thermal stress in the loading direction near the interface and it was significantly higher at LNT than that at RT. It was also shown that the replacement of the Al alloy rod to Ti rod of which the coefficient of thermal expansion is close to that of bulks significantly increased the tensile strength.

Original languageEnglish
Pages (from-to)639-643
Number of pages5
JournalPhysica C: Superconductivity and its applications
Volume426-431
Issue numberI
DOIs
Publication statusPublished - 2005 Oct 1
EventProceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity -
Duration: 2004 Nov 232004 Nov 25

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Keywords

  • FEM analysis
  • Liquid nitrogen temperature
  • Rare earth based bulk
  • Tensile test
  • Thermal stress

ASJC Scopus subject areas

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

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