Molecular dynamics study of Li0.6Pb0.4 binary alloy using first principle (original) (raw)
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Computer simulation of the liquid Li4Pb alloy
1985
Résumé Une simulation sur ordinateur de l'alliage liquide Li 4 Pb à 1085 K est présentée. Le calcul est fondé sur les potentiels de paire utilisés par Copestake et al. pour décrire la structure de ce système: interactions de Coulomb écrantées plus une répulsion de coeur mou. Les coefficients de diffusion ainsi que les fonctions de structure statiques et dynamiques sont évalués et comparés aux résultats expérimentaux. Les fonctions de corrélations de paires sont aussi calculées.
Interatomic potential for the compound-forming Li–Pb liquid alloy
Journal of Nuclear Materials, 2014
Atomistic simulations of liquid alloys face the challenge of correctly modeling basic thermodynamic properties. In this work we present an interatomic potential for the Li-Pb system, as well as a study of physical properties of Li-Pb alloys. Despite the complexity due to Li-Pb being a compound forming system where charge transfer is expected, we show here how the empirical EAM formalism is able to satisfactorily describe several physical properties in a wide range of Li concentration. Application of our potential to Li-Pb eutectic allows us to correctly predict many physical properties observed experimentally and calculated with ab initio techniques, providing in this way a potential suitable for future studies in the context of tritium breeder blanket designs in Fusion technology.
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Journal of Nepali Physical Society, 2022
We have used quasi-lattice theory to describe the mixing behavior of Bi-Pb liquid alloys at a temperature of 700K by computing thermodynamic functions and structural functions. The thermodynamic functions includes free energy of mixing(G M), activity (a), heat of mixing (H M), entropy of mixing (S M). The structural functions includes concentration fluctuation in the long-wavelength limit (S cc (0)) and chemical short range order parameter (α 1). Most of the computed values are in good agreement with the experimental data. The pair-wise interaction energies between the species of the liquid alloys play important role and are found to temperature dependent. Theoretical analysis suggests that Pb 3 Bi complex exists in the liquid state at 700K. And, it has hetero-coordination (i.e. ordering) nature but is of weakly interacting in nature.
Thermophysical properties of the Li(17)Pb(83)alloy
Fusion Engineering and Design, 1991
This paper describes a part of the work performed on the determination of the thermophysical properties of alloys in the binary system Li-Pb. The preparation of the eutectic alloy from the pure elements and its characterization using chemical analysis, metallography, thermal and thermal differential analysis is described. Results of the measurements of the following properties are presented: latent heat of fusion, specific heat, density, thermal expansion, thermal and electric conductivity and viscosity. The wetting behaviour of Li(17)Pb(83) against SS 316 is discussed in terms showing the influence of especially of oxygen on the wetting angle in this system.
KfK 4]44 THERMOPHYSICAL PROPERTIES IN THE SYSTEM Li-Pb Part I: Preparation andcharacterization of Li(17)Pb(83) eutectic alloy and the Lipb intermetallic compound U. Jauch, V. Karcher, B. Schulz Part 11: Thermophysical properties of Li(17)Pb(83) eutectic alloy Abstract Part I: Preparation and Characterization of Li(17)Pb(83) eutectic alloy and the LiPb intermetallic compound Part 11: Thermophysical properties of Li(17)Pb(83) eutectic alloy Part 111: Estimation of the thermophysical properties in the system Li-Pb page 2 25 45 -1 -General Abstract This report describes the work performed on the determination of the thermophysical properties of alloys in the binary system lithium-lead, within the frame of theKfK-project of nuclear fusion technology. The preparation of the Li(J7)Pb(83) alloy and the intermetallic compound Lipb from the pure elements determines the contents of part I of the report, which includes too the characterization of the materials using chemical analysis, metallography, thermal and thermal differential analysis. The great importance of the characterization especially of the metallography is shown in presenting some results of the eutectic alloy fabricated by different producers under technical conditions. Because of the great importance of the thermophysical behaviour of the liquid eutectic Li(17)Pb(83) for the design of a liquid metal breeder blanket in the next European Torus, part 11 of the report describes the measurements and results of the thermodynamic properties (latent heat of fusion, specific heat, density, thermal expansion and surface energy) of this alloy. The results of the determination of the transport properties (thermal and electrical conductivity and viscosity) are presented, too. In part 111 the methods are given, which lead to an estimation of thermophys ical properties of Li-compounds with high Li-contents (> 50 at.%) in the solid state. -2 -THERMOPHYSICAL PROPERTIES IN THE SYSTEM Li-Pb Part I Preparation and Characterization of the Li(17)Pb(83) eutectic &lloy and the LiPb intermetallic compound U. Jauch, V. Karcher, B. Schu1z Kernforschungszentrum Kar1sruhe Institut für Materia1-und Festkörperforschung Abstract Li(17)Pb(83) and LiPb were prepared from the pure elements in amounts of seve-ra1 hundred grams. The reso1idified samp1es were characterized by me1ting points (eutectic temperature), chemica1 analysis and meta110graphy. Using differential thermal analysis the heats of fusion were determined and the behaviour of the intermetallic phase LiPb in vacuum and high purified He was studied. The resu1ts from these investigations were app1ied to characterize Contents List of figures List of tables page 47 48 1 •
Static structure and dynamics of the liquid Li-Na and Li-Mg alloys
Physical Review E, 1998
We present calculations for the static structure and ordering properties of two lithium-based s-p bonded liquid alloys, Li-Na and Li-Mg. Our theoretical approach is based on the neutral pseudoatom method to derive the interatomic pair potentials, and on the modified-hypernetted-chain theory of liquids to obtain the liquid static structure, leading to a whole combination that is free of adjustable parameters. The study is complemented by performing molecular dynamics simulations which, besides checking the theoretical static structural results, also allow a calculation of some dynamical properties. The obtained results are compared with the available experimental data. ͓S1063-651X͑98͒07110-4͔
Structure factors and phonon dispersion in liquid Li 0.61 Na 0.39 alloy
Pramana-journal of Physics, 2004
The phonon spectra for liquid Li and Na have been computed through the phenomenological model of Bhatia and Singh for disordered systems like liquids and glasses and the obtained results have been compared with the available data obtained by inelastic neutron scattering (INS) and inelastic X-ray scattering (IXS) experiments. The effective pair potentials and their space derivatives are important ingredients in the computation of the dispersion curves. The pair potentials are obtained using the pseudo-potential theory. The empty core model proposed by Ashcroft is widely used for pseudo-potential calculations for alkali metals. But, it is thought to be unsuitable for Li because of its simple 1s electronic structure. However, it can be used with an additional term known as Born-Mayer (BM) core term. The influence of the BM core term on the phonon dispersion is discussed. The same pseudo-potential formalism has been employed to obtain the dispersion relation in liquid Li0.61Na0.39 alloy. Apart from the phonon spectra, the Ashcroft-Langreth structure factors in the alloy are derived in the Percus-Yevick approximation.
Physical Review B, 2019
Ab initio molecular dynamics simulations were performed to analyze changes in the structure and dynamics of molten Pb along the melting line for pressures ranging from ambient to 70 GPa. Common neighbor analysis reveals a local structural order of the underlying crystalline phase at the corresponding pressure, which increasingly competes with the existing icosahedral local order with pressure. Obtained dispersions of longitudinal and transverse collective excitations contain two branches of transverse modes for all pressures. Analysis of the pressure dependence of observed two-peak structure of the Fourier spectra of velocity autocorrelation functions allowed us to identify their peak locations with the frequencies of nonpropagating transverse branches in the second pseudo-Brillouin zone.
On the dynamical properties of the liquid Li–Na alloy
Journal of Non-Crystalline Solids, 1999
Several dynamical properties of the liquid Li±Na alloy have been studied by both molecular dynamics simulations and by a theoretical memory function formalism. We present results for the Li 0X61 Na 0X39 system where comparison is performed with the experimental inelastic neutron scattering data. The obtained results for the partial dynamic structure factors reveal the existence of propagating sound modes for wavevectors k`1.4 # A À1 . Ó 0022-3093/99/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 -3 0 9 3 ( 9 9 ) 0 0 2 6 2 -8
Thermodynamics and structure of liquid binary alloys calculated using an analytic pair potential
Physical Review B, 1994
Analytic pair potentials proposed by Pettifor and Ward are developed using the Heine-Abarenkov pseudopotential for Li-Na, ¹K, and Na-Cs liquid binary alloys. The corresponding partial structure factors are calculated using the random-phase approximation. The calculated thermodynamic and structural properties using this real-space formalism are in good agreement with experiments.