Thermal equation of state, and melting and thermoelastic properties of bcc tantalum from molecular dynamics

Liu, Zhongli; Zhang, Xiu-Lu; Cai, Ling-Cang; Chen, Xiangrong; Wu, Qiang; Jing, Fuqian

doi:10.1016/j.jpcs.2008.07.009

Cited by 16 publications

(10 citation statements)

References 54 publications

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“…To validate the scientific design and rational application, it is crucial to make the equation-ofstate of Ta well-informed. However, the melting curves of Ta, obtained from shock-wave compression, 3 DAC experiments, [4][5][6][7][8] and theoretical methods, [9][10][11][12][13][14][15][16][17][18] show great inconsistencies up to now.…”

Section: Introductionmentioning

confidence: 99%

“…However, no agreement has been reached among them at the moment. On the other hand, a series of theoretical melting curves produced from various methods have been reported during the recent ten years, such as density-functional-theories (DFT) based on mean-field potentials, 9 molecular dynamics (MD) simulations with different potentials (i.e., embedded-atom method (EAM), 10 extended Finnis-Sinclair (EFS), 11,12 and the model generalized pseudopotential theory (MGPT) potentials 13,14 ), and the DFT-based ab initio MD simulations 18 also produced inconsistent results. Among these alternative methods, MD simulations with relevant potentials draw more attentions due to the advantage of simulating huge systems.…”

Section: Introductionmentioning

confidence: 99%

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Melting curves and structural properties of tantalum from the modified-Z method

Liu

Cheng

et al. 2015

Journal of Applied Physics

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The melting curves and structural properties of tantalum (Ta) are investigated by molecular dynamics simulations combining with potential model developed by Ravelo et al. [Phys. Rev. B 88, 134101 (2013)]. Before calculations, five potentials are systematically compared with their abilities of producing reasonable compressional and equilibrium mechanical properties of Ta. We have improved the modified-Z method introduced by Wang et al. [J. Appl. Phys. 114, 163514 (2013)] by increasing the sizes in L x and L y of the rectangular parallelepiped box (L x ¼ L y (L z). The influences of size and aspect ratio of the simulation box to melting curves are also fully tested. The structural differences between solid and liquid are detected by number density and local-order parameters Q 6. Moreover, the atoms' diffusion with simulation time, defects, and vacancies formations in the sample are all studied by comparing situations in solid, solid-liquid coexistence, and liquid state. V

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Melting curves and structural properties of tantalum from the modified-Z method

Liu

Cheng

et al. 2015

Journal of Applied Physics

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“…Theoretically, the empirical melting models (including Lindemann law, 1 phenomenological vacancy model, 2 and dislocation melting model) 3 and the simulation methods based on density functional theory 4 and classical molecular dynamics (MD) using empirical potentials 5 have been applied to investigate the melting behaviors of materials under compression. Despite extensive experimental [6][7][8][9] and theoretical [10][11][12][13] studies have been performed on the melting properties of transition metals in the past decade, large discrepancies still exist among their DAC, 6,14,15 SW, 16,17 and theoretical results. [18][19][20][21] For instance, very recently, Pozzo et al 13 reported a melting curve of Ni under pressure up to 100 GPa based on ab initio MD calculations.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of the melting curve of NiAl alloy under pressure

2014

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The melting curve of B2-NiAl alloy under pressure has been investigated using molecular dynamics technique and the embedded atom method (EAM) potential. The melting temperatures were determined with two approaches, the one-phase and the two-phase methods. The first one simulates a homogeneous melting, while the second one involves a heterogeneous melting of materials. Both approaches reduce the superheating effectively and their results are close to each other at the applied pressures. By fitting the well-known Simon equation to our melting data, we yielded the melting curves for NiAl: 1783(1 + P/9.801)0.298 (one-phase approach), 1850(1 + P/12.806)0.357 (two-phase approach). The good agreement of the resulting equation of states and the zero-pressure melting point (calc., 1850 ± 25 K, exp., 1911 K) with experiment proved the correctness of these results. These melting data complemented the absence of experimental high-pressure melting of NiAl. To check the transferability of this EAM potential, we have also predicted the melting curves of pure nickel and pure aluminum. Results show the calculated melting point of Nickel agrees well with experiment at zero pressure, while the melting point of aluminum is slightly higher than experiment.

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“…So the refinement of the high‐pressure elastic constants is urgently needed for Ta as an important pressure standard. As a part of the systematic study of the high‐pressure properties of metal Ta, we have previously investigated the melting properties 17, the EOS and the thermodynamic properties of Ta 5, 27 under pressure; in this paper, we focus on the refinement of the elastic properties of Ta at extremely high pressure up to 500 GPa.…”

Section: Introductionmentioning

confidence: 99%

FP‐LAPW calculations of structural and elastic properties of tantalum under high pressure

Liu

Cai³

et al. 2011

Physica Status Solidi (b)

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We have revisited and refined the high-pressure elastic properties of body-centered-cubic Ta using the accurate allelectron full potential linearized augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT). Based on the total energy calculations, we first deduced the accurate static equation of state (EOS) of Ta. Then we derived the elastic constants, C 11 , C 12 , and C 44 under pressure up to 500 GPa using the pressure-correction method which corrected the previous method theoretically, and the calculated elastic constants agree well with experiment under high pressure. From the accurately determined elastic constants, we also discussed the elastic anisotropy and the sound velocities of Ta at high pressure. The predicted Debye temperature at 0 GPa and 0 K is in good agreement with experiment, and the Debye temperature increases monotonously as pressure increases.

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Thermal equation of state, and melting and thermoelastic properties of bcc tantalum from molecular dynamics

Cited by 16 publications

References 54 publications

Melting curves and structural properties of tantalum from the modified-Z method

Melting curves and structural properties of tantalum from the modified-Z method

Molecular dynamics simulations of the melting curve of NiAl alloy under pressure

FP‐LAPW calculations of structural and elastic properties of tantalum under high pressure

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