Swelling due to fission products and additives dissolved within the uranium dioxide lattice

Middleburgh, Simon C.; Grimes, Robin W.; Desai, K.; Blair, Paul; Hallstadius, Lars; Backman, K.; Uffelen, P. Van

doi:10.1016/j.jnucmat.2012.03.037

Cited by 37 publications

(20 citation statements)

References 45 publications

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“…A disordered solid solution is expected to form for [27] it is shown that HEAs which display intermetallic compounds cannot be discerned from those that do not. This effect is replicated in Figure 1.…”

Section: Current State-of-the-artmentioning

confidence: 99%

“…where r is commonly taken to be the Goldschmit atomic radius of element i and r is the weighted average of the systems atomic radii. This is also included in Yang et al's prediction whereby a value of δ ≤ 6.6 indicates a disordered solid solution should form [27].…”

Section: Current State-of-the-artmentioning

confidence: 99%

“…Although the magnitudes of values are not precise, the relative values are very similar and therefore can be compared within the same model. Yang et al [27] suggests that no SPHEA exists for δ ≥ 6.6. Interestingly, the NbTiV2Zr alloy is the only system that has both Φ > 1 and δ > 6.6.…”

Section: Benchmarking To Experimental Literaturementioning

confidence: 99%

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Predicting the formation and stability of single phase high-entropy alloys

King

Middleburgh

McGregor³

et al. 2016

Acta Materialia

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344

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Abstract:A method for rapidly predicting the formation and stability of undiscovered single phase high-entropy alloys (SPHEAs) is provided. Our software implementation of the algorithm uses data for 73 metallic elements and rapidly combines them -4, 5 or 6 elements at a time -using the Miedema semi-empirical methodology to yield estimates of formation enthalpy. Approximately 186,000,000 compositions of 4, 5 and 6 element alloys were screened, and ~1,900 new equimolar SPHEAs predicted. Of the 185 experimentally reported HEA systems currently known, the model correctly predicted the stability of the SPHEA structure in 177. The other sixteen were suggested to actually form a partially ordered solid solution -a finding supported by other recent experimental and theoretical work. The stability of each alloy at a specific temperature can also be predicted, allowing precipitation temperatures (and the likely precipitate) to be forecast. This combinatorial algorithm is described in detail, and its software implementation is freely accessible through a webservice allowing rapid advances in the design, development and discovery of new technologically important alloys. , and re-iterated by others since then [1,12], defines a HEA as any alloy consisting of 5 or more elements between 5 -35 at. %. As such, this type of HEA will usually possess a microstructure consisting of two or more distinct phases, some of which are likely to be brittle intermetallic compounds. Although, multiphase strengthening is sometimes desirable in alloys, a large amount of any brittle phase will generally make an alloy unusable as a structural material and such HEAs are therefore mundane. However, as will be discussed shortly, in a few special cases, the additional entropy of the multi-element composition will stabilise a microstructure consisting of either (i) a single solid solution having one of the simple close-packed crystal structures (FCC, HCP or BCC) or (ii) a duplex microstructure consisting of two such simple solid solutions. Generally, it is these non-trivial examples of HEA that interest investigators.This is because the resulting random solid solution(s) will exhibit a combination of ductility coupled with significant solid solution hardening. We recommend use of the term single 2 phase high-entropy alloy (SPHEA) as a more restrictive term to differentiate the rare and desirable single phase type of HEA from generic examples of multiphase HEAs.Combining Yeh's compositional limits [7] with the requirement for a single phase solid solution, we can define a SPHEA as an alloy with  4 alloying elements, at least 4 of which with a molar ratio between 0.33 -1 to that of the highest contributing element. These alloys must be able to display a single phase of simple, random, close-packed structure below the solidus.We return now to the factors that might stabilise a SPHEA. The prevailing hypotheses were (i) that the simple crystal structure or structures are thermodynamically stabilised, relative to possible intermetallic compounds, by the inc...

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Section: Current State-of-the-artmentioning

confidence: 99%

Section: Current State-of-the-artmentioning

confidence: 99%

See 1 more Smart Citation

Predicting the formation and stability of single phase high-entropy alloys

King

Middleburgh

McGregor³

et al. 2016

Acta Materialia

Self Cite

344

120

View full text Add to dashboard Cite

show abstract

“…Also the TRANSURANUS code benefits from such an approach. The radial redistribution of actinides in mixed oxide fuels [44] and the solid fission product swelling model [3] have been published recently. In the current paper, a new mesco-scopic model for the intra-granular fission gas behaviour in UO2 is proposed that constitutes an extension of the formulation of Speight.…”

Section: Discussionmentioning

confidence: 99%

“…Molecular dynamics computations were applied for extracting the thermal expansion and thermal conductivity of un-irradiated UO2 fuel and implementing the correlation in the FRAPCON code [1]. A similar molecular dynamics analysis was carried out to simulate the interaction of a He or Xe filled bubble with a fission fragment [2], or empirical potential simulations were applied in order to predict swelling due to soluble solid fission in a fuel performance code [3]. This has led to an improved assessment of the resolution process coefficient, which remains up until now a fitting parameter in several fission gas release models of fuel performance codes.…”

Section: Introductionmentioning

confidence: 99%