Pressure dependence of anomalous diffusion of zirconium in {beta}-titanium
- Osaka Univ., Suita (Japan)
- Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research
The impurity diffusion coefficients of Zr in {beta}-Ti have been determined at temperatures from 1,173 to 1,773 K under pressures of 0.1 MPa and 1.0, 2.1, and 3.0 GPa using Ti/Ti-3.06 at. pct Zr diffusion couples. The Arrhenius plots of the diffusion coefficients exhibit strong curvature, and their degree becomes larger with increasing pressure. The activation volumes, {Delta}V, evaluated from the isothermal pressure dependence of the diffusion coefficient are 0.22 to 0.36 {Omega}, where {Omega} is the atomic volume of the host metal. The values of {Delta}V/{Omega} are very close to the ratio of 0.33 for self-diffusion in {beta}-Ti reported by Jeffery and the ratios of 0.28 to 0.41 for W and Sn diffusion in {beta}-Ti reported by Araki et al., whereas they are considerably smaller than that normally expected for diffusion in bcc metals via simple monovacancy mechanism. The increase in degree of curvature in the Arrhenius plot by pressure and the small values of {Delta}V/{Omega} can be interpreted in terms of the model of phonon-assisted diffusion jumps via monovacancies.
- OSTI ID:
- 282231
- Journal Information:
- Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 7 Vol. 27; ISSN 0360-2133; ISSN MTTABN
- Country of Publication:
- United States
- Language:
- English
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