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Journal of Materials Science

, Volume 30, Issue 13, pp 3369–3375 | Cite as

Superplastic behaviour of YBa2Cu3O7−x/Ag superconductors

  • Byoung-Chul Kim
  • Jeong-Tae Kim
  • Jin-Tae Song
Article

Abstract

High-temperature deformation characteristics of YBa2Cu3O7−x oxide (YBCO) and YBa2Cu3O7−x/Ag composite (YBCO/Ag) in uniaxial compression have been investigated. A compression test was carried out at temperatures from 780–930°C at initial strain rates between 10−6 and 10−4 s−1. YBCO/Ag composites with fine, dense and equiaxed grains were compressed over 120% with no indication of failure at higher temperatures, and the strain-rate sensitivity exponent, m, was found to be about 0.42–0.46 between 890 and 930°C. They are considered to be one indication of superplasticity. The activation energy for deformation was 500–580 KJ mol−1. The specimens suffered grain growth slightly during the deformation at 930°C and the majority of growth might be a function of exposure time, temperature and silver content, but each grain maintained the equiaxed shape after extensive superplastic deformation. This is consistent with a grain-boundary sliding mechanism. The silver at grain boundaries acts to decrease the activation energy for deformation and promote the grain-boundary sliding.

Keywords

Oxide Polymer Activation Energy Exposure Time Compression Test 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • Byoung-Chul Kim
    • 1
  • Jeong-Tae Kim
    • 2
  • Jin-Tae Song
    • 2
  1. 1.Korea Atomic Energy Research InstituteTaejonKorea
  2. 2.Department of Materials EngineeringHanyang UniversitySeoulKorea

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