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Title: Development of an N -body interatomic potential for hcp and bcc zirconium

Abstract

An interatomic potential based on the second-moment approximation of the tight-binding scheme is developed for zirconium, by fitting its four adjustable parameters to the cohesive energy, atomic volume, and elastic constants of the hcp phase. In this work we attempt to model realistically two different crystallographic phases of a solid with the same potential. The reliability of our potential is tested in both the hcp and the bcc phases with regard to defect properties, thermal expansion, phonon properties, and mean-square displacements. For this purpose, we perform quenched molecular-dynamics relaxations, quasiharmonic lattice-dynamics calculations, and molecular-dynamics simulations. The low vacancy-formation and migration energies found in the bcc phase are consistent with the fast diffusivity experimentally observed. Unlike some other {ital N}-body potentials recently proposed to model bcc transition metals, our potential is not affected by the flaw of unphysical or even negative thermal expansion. We obtain thermal expansions that agree well with experiments in both phases, although they turned out to be slightly too large. The phonon-dispersion curves and, in particular, the anomalies in the bcc phase are well reproduced. We emphasize the stabilization with temperature of the {ital T}1 {ital N}-point phonon of the bcc phase, which is related to themore » bcc- to hcp-phase transition. We obtain a temperature dependence of this mode much weaker than in the experimental case. This influences the temperature behavior of the vibrational properties: In particular the mean-square displacement is markedly higher than the one extracted from experiments in the bcc phase at high temperatures. On the other hand, mean-square displacements in the hcp phase are in excellent agreement with experiment.« less

Authors:
 [1];  [2]
  1. Centre d'Etudes de Saclay, Section de Recherches de Metallurgie Physique, 91191 Gif-sur-Yvette CEDEX, France (FR)
  2. Laboratoire des Composes Non-Stoechiometriques, Universite de Paris-Sud, 91405 Orsay CEDEX, France (FR)
Publication Date:
OSTI Identifier:
5492741
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter; (USA)
Additional Journal Information:
Journal Volume: 43:14; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ZIRCONIUM; INTERATOMIC FORCES; BCC LATTICES; HCP LATTICES; LATTICE VIBRATIONS; PHONONS; THERMAL EXPANSION; CRYSTAL LATTICES; CRYSTAL STRUCTURE; CUBIC LATTICES; ELEMENTS; EXPANSION; HEXAGONAL LATTICES; METALS; QUASI PARTICLES; TRANSITION ELEMENTS; 360104* - Metals & Alloys- Physical Properties; 656002 - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)

Citation Formats

Willaime, F, and Massobrio, C. Development of an N -body interatomic potential for hcp and bcc zirconium. United States: N. p., 1991. Web. doi:10.1103/PhysRevB.43.11653.
Willaime, F, & Massobrio, C. Development of an N -body interatomic potential for hcp and bcc zirconium. United States. https://doi.org/10.1103/PhysRevB.43.11653
Willaime, F, and Massobrio, C. 1991. "Development of an N -body interatomic potential for hcp and bcc zirconium". United States. https://doi.org/10.1103/PhysRevB.43.11653.
@article{osti_5492741,
title = {Development of an N -body interatomic potential for hcp and bcc zirconium},
author = {Willaime, F and Massobrio, C},
abstractNote = {An interatomic potential based on the second-moment approximation of the tight-binding scheme is developed for zirconium, by fitting its four adjustable parameters to the cohesive energy, atomic volume, and elastic constants of the hcp phase. In this work we attempt to model realistically two different crystallographic phases of a solid with the same potential. The reliability of our potential is tested in both the hcp and the bcc phases with regard to defect properties, thermal expansion, phonon properties, and mean-square displacements. For this purpose, we perform quenched molecular-dynamics relaxations, quasiharmonic lattice-dynamics calculations, and molecular-dynamics simulations. The low vacancy-formation and migration energies found in the bcc phase are consistent with the fast diffusivity experimentally observed. Unlike some other {ital N}-body potentials recently proposed to model bcc transition metals, our potential is not affected by the flaw of unphysical or even negative thermal expansion. We obtain thermal expansions that agree well with experiments in both phases, although they turned out to be slightly too large. The phonon-dispersion curves and, in particular, the anomalies in the bcc phase are well reproduced. We emphasize the stabilization with temperature of the {ital T}1 {ital N}-point phonon of the bcc phase, which is related to the bcc- to hcp-phase transition. We obtain a temperature dependence of this mode much weaker than in the experimental case. This influences the temperature behavior of the vibrational properties: In particular the mean-square displacement is markedly higher than the one extracted from experiments in the bcc phase at high temperatures. On the other hand, mean-square displacements in the hcp phase are in excellent agreement with experiment.},
doi = {10.1103/PhysRevB.43.11653},
url = {https://www.osti.gov/biblio/5492741}, journal = {Physical Review, B: Condensed Matter; (USA)},
issn = {0163-1829},
number = ,
volume = 43:14,
place = {United States},
year = {1991},
month = {5}
}