期刊
PHYSICAL REVIEW B
卷 79, 期 5, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevB.79.054304
关键词
ab initio calculations; aluminium; impurities; reaction kinetics theory; self-diffusion; vacancies (crystal)
资金
- Fundamental Research on Matter (FOM) of the Netherlands [02EMM032]
- Materials Innovation Institute92
- Netherlands Foundation for Scientific Research (NWO) [SH-007-07]
- [MC4.05212]
Activation energies for vacancy-mediated impurity diffusion in face-centered-cubic aluminum have been computed ab initio for all technologically important alloying elements, as well as for most of the lanthanides. The so-called five-frequency rate model is used to establish the limiting vacancy interchange process. Many elements were shown to be limited by Al-vacancy interchanges. For these elements we showed that the diffusion activation energy is rather close to that for Al self-diffusion, and additionally the diffusion pre-exponential factor is of the same order as that for Al self-diffusion. The diffusion activation energy is shown to exhibit a linear relation with the solute partial molar volume in Al. In contrast, transition metals are shown to deviate strongly from these generalities. Diffusion of transition-metal atoms is limited by solute-vacancy interchanges that require remarkably high activation energies. Transition-metal diffusivities in Al show strong trends with the number of d-valence electrons but not with partial molar volume.
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