| 1. |
- Li, R., et al.
(författare)
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First-principles study of the behavior of O, N and C impurities in vanadium solids
- 2013
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 435:1-3, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- Vanadium alloys are promising candidate for the structural materials of first-wall in future fusion reactor. In realistic vanadium alloys, there always exist some impurities (e.g. oxygen, nitrogen and carbon). To understand the microscopic behavior of these impurities, we investigated energetic and diffusion of O, N and C impurities as well as O-O/N-N/C-C interactions in pure vanadium using first-principles calculations. The O, N and C atoms prefer to occupy an octahedral interstitial site, and exhibit high diffusion barrier with 1.23 eV, 1.48 eV and 1.14 eV via diffusing between two neighboring octahedral interstitial sites, respectively. Such high barriers indicate that these impurities are hard to diffuse inside bulk vanadium. The corresponding diffusion coefficients as function of temperature were estimated using the Arrhenius diffusion equation. Our theoretical results provide the fundamental parameters for understanding the impurity effects in early stage of irradiation damage.
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| 2. |
- Li, Xiaoqing, et al.
(författare)
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Ideal strength of random alloys from first principles
- 2013
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 87:21, s. 214203-
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Tidskriftsartikel (refereegranskat)abstract
- The all-electron exact muffin-tin orbitals method in combination with the coherent-potential approximation was employed to investigate the ideal tensile strengths of elemental V and Mo solids, and V-and Mo-based random solid solutions. Under uniaxial [001] tensile loading, the ideal tensile strength of V is 11.6 GPa and the lattice fails by shear. Assuming isotropic Poisson contraction, the ideal tensile strengths are 26.7 and 37.6 GPa for V in the [111] and [110] directions, respectively. The ideal strength of Mo is 26.7 GPa in the [001] direction and decreases when a few percent of Tc is introduced in Mo. For the V-based alloys, Cr increases and Ti decreases the ideal tensile strength in all principal directions. Adding the same concentration of Cr and Ti to V leads to ternary alloys with similar ideal strength values as that of pure V. The alloying effects on the ideal strength are explained using the electronic band structure.
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