Fatigue behavior at room temperature and its influence on superconducting properties of Nb 3 Al composite wire

Takehiro Sawada, Shojiro Ochiai, Masaki Hojo, Yuichi Yamada, Kenichi Takahashi, Naoki Ayai, Kazuo Watanabe

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The fatigue behavior at room temperature and its influence on the superconducting properties of Nb 3 Al composite wire with a copper ratio of 1.55, containing 241 Nb 3 Al filaments with an average diameter of 34 μm, were studied. The main results are summarized as follows. (1) Fatigue cracks nucleated and grew in the matrix (Cu), and thereby caused the fracture of Nb 3 Al filaments. The Nb 3 Al filaments themselves were not fractured by fatigue. (2) The growth pattern of the fatigue cracks depends on the maximum-applied-stress (σ c, max ) level. (a) At high σ c, max , overall fracture of the composite occurs before the growth of fatigue cracks. The filaments are merely broken except in the fracture surface as in the case of the static test. (b) At intermediate σ c, max , fatigue cracks can grow at several points before the breakage of the composite. Thus the breakages of the filaments are accumulated not only in the fracture surface, but also in the whole body. (c) At low σ c, max , one fatigue crack grows in advance of others, causing the breakage of the composite. Thus the filaments are broken only in the fracture surface. (3) Corresponding to the growth patterns of the fatigue cracks mentioned in (2), the result of the measurement of critical current (2), using the rest part of the broken composite after the fatigue test shows the reduction in I c at intermediate σ c, max , but not at high and low σ c, max .

Original languageEnglish
Pages (from-to)822-828
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume61
Issue number9
DOIs
Publication statusPublished - 1997 Jan 1

Keywords

  • Crack growth
  • Critical current
  • Fatigue
  • Residual strength

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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