High-pressure structural studies of UC by v-ray diffraction and synchrotron radiation

Olsen, J. Staun; Gerward, L.; Benedict, U.; Itié, J. P.; Richter, K.‐L.

doi:10.1016/0022-5088(86)90561-8

Cited by 38 publications

(3 citation statements)

References 9 publications

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“…Apart from this, the other plausible structures especially low symmetry tetragonal and orthorhombic structures have not been considered for structural stability analysis in previous study. 18 As, it has been shown experimentally 19 and theoretically 11 that the actinide monocarbide UC displays a transition from higher symmetry B1 phase to a lower symmetry orthorhombic phase under high pressure, it is worth to consider the lower symmetry structures for structural stability analysis of ThC also. In view of these shortcomings of the previous study, we have performed detailed ab-initio investigations on ThC to examine the several aspects of structural stability of this material under hydrostatic compression.…”

Section: Introductionmentioning

confidence: 99%

Prediction of new high pressure structural sequence in thorium carbide: A first principles study

Sahoo

Joshi

Gupta

2015

Journal of Applied Physics

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Ab initio calculations on structural, elastic and dynamic stability of CdO at high pressures J. Appl. Phys. 112, 093523 (2012); 10.1063/1.4764899First-principles investigations of elastic stability and electronic structure of cubic platinum carbide under pressureIn the present work, we report the detailed electronic band structure calculations on thorium monocarbide. The comparison of enthalpies, derived for various phases using evolutionary structure search method in conjunction with first principles total energy calculations at several hydrostatic compressions, yielded a high pressure structural sequence of NaCl type (B1) ! Pnma ! Cmcm ! CsCl type (B2) at hydrostatic pressures of $19 GPa, 36 GPa, and 200 GPa, respectively. However, the two high pressure experimental studies by Gerward et al. [J. Appl. Crystallogr. 19, 308 (1986); J. Less-Common Met. 161, L11 (1990)] one up to 36 GPa and other up to 50 GPa, on substoichiometric thorium carbide samples with carbon deficiency of $20%, do not report any structural transition. The discrepancy between theory and experiment could be due to the non-stoichiometry of thorium carbide samples used in the experiment. Further, in order to substantiate the results of our static lattice calculations, we have determined the phonon dispersion relations for these structures from lattice dynamic calculations. The theoretically calculated phonon spectrum reveal that the B1 phase fails dynamically at $33.8 GPa whereas the Pnma phase appears as dynamically stable structure around the B1 to Pnma transition pressure. Similarly, the Cmcm structure also displays dynamic stability in the regime of its structural stability. The B2 phase becomes dynamically stable much below the Cmcm to B2 transition pressure. Additionally, we have derived various thermophysical properties such as zero pressure equilibrium volume, bulk modulus, its pressure derivative, Debye temperature, thermal expansion coefficient and Gruneisen parameter at 300 K and compared these with available experimental data. Further, the behavior of zero pressure bulk modulus, heat capacity and Helmholtz free energy has been examined as a function temperature and compared with the experimental data of Danan [J. Nucl. Mater. 57, 280 (1975)]. V C 2015 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 99%

Prediction of new high pressure structural sequence in thorium carbide: A first principles study

Sahoo

Joshi

Gupta

2015

Journal of Applied Physics

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“…При этом понимание свойств уран-углеродных (UC) систем важно не только в связи с их потенциальной кандидатурой для применения в атомной промышленности, но и с точки зрения фундаментальной науки. Однако что касается поведения UC при высоком давлении, в литературе существует очень мало экспериментальных и теоретических исследований по этому материалу [19][20][21][22][23]. Похожая ситуация наблюдается и с другими тугоплавкими карбидами, в частности с карбидами тантала ТаС и гафния HfC, а также с их смесями, которые имеют аномально высокие температуры плавления около 4000 K, и при этом сохраняют высокую прочность и долговечность при экстремальных тепловых нагрузках.…”

Section: Introductionunclassified

Численное Моделирование Поведения Карбидов При Высокоэнергетическом Воздействии

Маевский

2022

Журнал Технической Физики

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The results of research on modeling thermodynamic parameters of shock-wave loading of carbides with different stoichiometric ratios are presented. The carbides are considered as a mixture of carbon with the corresponding component. The calculations of pressure, compression and temperature values under shock-wave loading for solid and porous carbides in the range of pressure values above 3 GPa are performed. The model calculations are compared with the known experimental results on the shock-wave loading of carbides with different porosity values. The possibility of modeling the behavior according to the proposed method for carbides for which there are no experimental data at high dynamic loads is shown.

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“…The high pressure behaviors of U-C [32][33][34] and U-Si [35,36] compounds have also been studied to evaluate their structural stabilities. The high-pressure behavior of UC 2 shows tetragonal → monoclinic → orthorhombic transition for this material with transition pressures of 8 GPa and 42 GPa [34].…”

Section: Introductionmentioning

confidence: 99%

Pressure Tuned Structural, Electronic and Elastic Properties of U3Si2C2: A First Principles Study

Guo

Shi

et al. 2021

Crystals

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U3Si2C2 is expected to be a new nuclear fuel as a ternary compound of uranium, silicon and carbon. However, the relevant research on U3Si2C2 under accident conditions is rarely reported. Hence it is necessary to explore the service behavior of the potential U-Si-C ternary nuclear fuel in extreme environments. In this work, the structural characteristics, electronic behaviors and mechanical properties of U3Si2C2, such as stable crystalline structures, density of states, charge distributions, electron localization function, electronic thermal conductivity and elastic modulus under extreme high pressure are calculated by density functional theory. The calculation results show that the lattice volume sharply increases when the external stress reached 9.8 GPa. Ionic and metallic nature coexist as to the bonding characteristics of U3Si2C2, and the ionic takes the dominant position in bonding. The toughness of U3Si2C2 is predicted to be better compared to U3Si2. Our theoretical investigation may help with the application of U3Si2C2-based fuel and the design of ternary uranium fuels.

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High-pressure structural studies of UC by v-ray diffraction and synchrotron radiation

Cited by 38 publications

References 9 publications

Prediction of new high pressure structural sequence in thorium carbide: A first principles study

Prediction of new high pressure structural sequence in thorium carbide: A first principles study

Численное Моделирование Поведения Карбидов При Высокоэнергетическом Воздействии

Pressure Tuned Structural, Electronic and Elastic Properties of U3Si2C2: A First Principles Study

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