Ways of improving the high-temperature work service of vanadium and some alloys used in reactors

Shyrokov, V. V.; Vasyliv, Kh. B.; Shyrokov, O. V.

doi:10.1016/j.jnucmat.2009.07.009

Cited by 22 publications

(7 citation statements)

References 3 publications

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“…2 Recently, V, Nb, and Ta have been found to undergo a martensitic-like structural distortion [3][4][5] in which they transform from the high-temperature bcc structure to either a rhombohedral structure or to a tetragonal structure. Apart from this, vanadium-based alloys are known to have the desired combination of physicomechanical properties, compatibility with nuclear fuel, and high resistance to corrosion 6,7 making them potential structural materials for fast-neutron nuclear power plants which can be operated at temperatures exceeding 1000 K for increasing the thermodynamic efficiency of electric power production.…”

Section: Introductionmentioning

confidence: 99%

First-principles calculation of phase equilibrium of V-Nb, V-Ta, and Nb-Ta alloys

et al. 2012

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In this paper, we report the calculated phase diagrams of V-Nb, V-Ta, and Nb-Ta alloys computed by combining the total energies of 40-50 configurations for each system (obtained using density functional theory) with the cluster expansion and Monte Carlo techniques. For V-Nb alloys, the phase diagram computed with conventional cluster expansion shows a miscibility gap with consolute temperature T c = 1250 K. Including the constituent strain to the cluster expansion Hamiltonian does not alter the consolute temperature significantly, although it appears to influence the solubility of V-and Nb-rich alloys. The phonon contribution to the free energy lowers T c to 950 K (about 25%). Our calculations thus predicts an appreciable miscibility gap for V-Nb alloys. For bcc V-Ta alloy, this calculation predicts a miscibility gap with T c = 1100 K. For this alloy, both the constituent strain and phonon contributions are found to be significant. The constituent strain increases the miscibility gap while the phonon entropy counteracts the effect of the constituent strain. In V-Ta alloys, an ordering transition occurs at 1583 K from bcc solid solution phase to the V 2 Ta Laves phase due to the dominant chemical interaction associated with the relatively large electronegativity difference. Since the current cluster expansion ignores the V 2 Ta phase, the associated chemical interaction appears to manifest in making the solid solution phase remain stable down to 1100 K. For the size-matched Nb-Ta alloys, our calculation predicts complete miscibility in agreement with experiment.

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Section: Introductionmentioning

confidence: 99%

First-principles calculation of phase equilibrium of V-Nb, V-Ta, and Nb-Ta alloys

et al. 2012

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Section: Available Online Xxxxmentioning

confidence: 99%

“…Moreover, the weight of the components, particularly for accelerating or rotating structural components is a major consideration and accordingly, alloy density is a key factor in materials selection. In this regard, vanadium is a promising material for specific structural applications as it provides the lowest density of the various high melting point metals; therefore, vanadium has much higher density-normalized ultimate tensile strength than nickel up to elevated temperatures [5].Some low-alloyed vanadium-based materials are the focus of current research; for example, alloy V-4Cr-4Ti was identified as an attractive material for self-cooled liquid Li blanket in fusion reactors [6]. Nevertheless, pure and low-alloyed vanadium have poor oxidation resistance [7,8].…”

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confidence: 99%

High temperature compression strength and oxidation of a V-9Si-13B alloy

Krüger

2016

Scripta Materialia

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“…Secondly, by using lightweight materials with similar mechanical properties compared to conventional materials, the reduction of mass inertia will also affect the efficiency of the process. Amongst other refractory metal-based alloys several new molybdenum and vanadium alloys, which follow the approaches described above, provide excellent mechanical properties in a wide temperature range, offering promising possibilities in terms of various high temperature applications [3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

Krüger

Schmelzer

Helmecke

2016

Metals

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V-Si-B and Mo-Si-B alloys are currently the focus of materials research due to their excellent high temperature capabilities. To optimize the mechanical alloying (MA) process for these materials, we compare microstructures, morphology and particles size as well as hardness evolution during the milling process for the model alloys V-9Si-13B and Mo-9Si-8B. A variation of the rotational speed of the planetary ball mill and the type of grinding materials is therefore investigated. These modifications result in different impact energies during ball-powder-wall collisions, which are quantitatively described in this comparative study. Processing with tungsten carbide vials and balls provides slightly improved impact energies compared to vials and balls made of steel. However, contamination of the mechanically alloyed powders with flaked particles of tungsten carbide is unavoidable. In the case of using steel grinding materials, Fe contaminations are also detectable, which are solved in the V and Mo solid solution phases, respectively. Typical mechanisms that occur during the MA process such as fracturing and comminution are analyzed using the comminution rate K P . In both alloys, the welding processes are more pronounced compared to the fracturing processes.

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Ways of improving the high-temperature work service of vanadium and some alloys used in reactors

Cited by 22 publications

References 3 publications

First-principles calculation of phase equilibrium of V-Nb, V-Ta, and Nb-Ta alloys

First-principles calculation of phase equilibrium of V-Nb, V-Ta, and Nb-Ta alloys

High temperature compression strength and oxidation of a V-9Si-13B alloy

Similarities and Differences in Mechanical Alloying Processes of V-Si-B and Mo-Si-B Powders

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