Self-diffusion along dislocations in ultra high purity iron

Yumiko Shima, Yukio Ishikawa, Hiroyuki Nitta, Yoshihiro Yamazaki, Kouji Mimura, Minoru Isshiki, Yoshiaki Iijima

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

Self-diffusion along dislocations in ultra high purity iron containing 0.5-1.2 mass ppm carbon, 0.1-1.0 mass ppm nitrogen and 1.8-4.0 mass ppm oxygen has been studied by the radioactive tracer method with the sputter-microsectioning technique. Below 700 K, the self-diffusion coefficient along dislocations has been determined directly from the type C kinetics classified by Harrison, whereas above 800 K it has been obtained by the type B kinetics assuming that the effective radius of dislocation pipe is equal to 5 × 10-10 m. The temperature dependence of the self-diffusion coefficient along dislocations does not show a linear Arrhenius relation. Below 900 K the Arrhenius plot shows slightly downward curvature. However, above 900 K the self-diffusion coefficient along dislocations increases remarkably with increasing temperature. The value at 900 K is 10-14 m2s-1, while it takes 10-10 m2s-1 at the Curie temperature (1043 K). It seems that the steep increase of the self-diffusion coefficient along dislocations near the Curie temperature is related to the magnetic transformation in ultra high purity iron.

Original languageEnglish
Pages (from-to)173-177
Number of pages5
JournalMaterials Transactions
Volume43
Issue number2
DOIs
Publication statusPublished - 2002 Feb

Keywords

  • Carbon segregation
  • Dislocation self-diffusion
  • Impurity-free dislocation
  • Lattice self-diffusion
  • Magnetic effect
  • Pipe diffusion
  • Ultra high purity iron

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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