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 language | English |
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Pages (from-to) | 173-177 |
Number of pages | 5 |
Journal | Materials Transactions |
Volume | 43 |
Issue number | 2 |
DOIs | |
Publication status | Published - 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