Publication result detail

The origin of lattice instability in bcc tungsten under triaxial loading

ČERNÝ, M.; ŘEHÁK, P.; POKLUDA, J.

Original Title

The origin of lattice instability in bcc tungsten under triaxial loading

English Title

The origin of lattice instability in bcc tungsten under triaxial loading

Type

WoS Article

Original Abstract

Stability of ideal bcc tungsten crystal under triaxial tensile loading was explored from first principles using an analysis of both elastic and dynamic stability. The triaxial stress state was considered a superposition of axial and biaxial transverse stresses. The region of attainable stresses which was delimited using the computed tensile stress maxima was marginally reduced by occurrence of soft phonons in the crystal lattice. While, under purely hydrostatic tension, the crystal was predicted stable up to 48GPa, greater magnitude of a differential stress reduced the value of a mean (hydrostatic) stress associated with first phonon instabilities to about 35GPa. This value is rather close to that recently determined in experiment. Computed phonon spectra were successfully verified with the help of atomistic models of microscopic lattice deformation.

English abstract

Stability of ideal bcc tungsten crystal under triaxial tensile loading was explored from first principles using an analysis of both elastic and dynamic stability. The triaxial stress state was considered a superposition of axial and biaxial transverse stresses. The region of attainable stresses which was delimited using the computed tensile stress maxima was marginally reduced by occurrence of soft phonons in the crystal lattice. While, under purely hydrostatic tension, the crystal was predicted stable up to 48GPa, greater magnitude of a differential stress reduced the value of a mean (hydrostatic) stress associated with first phonon instabilities to about 35GPa. This value is rather close to that recently determined in experiment. Computed phonon spectra were successfully verified with the help of atomistic models of microscopic lattice deformation.

Keywords

theoretical strength; triaxial loading; stress superposition; soft phonons; ab initio calculations

Key words in English

theoretical strength; triaxial loading; stress superposition; soft phonons; ab initio calculations

Authors

ČERNÝ, M.; ŘEHÁK, P.; POKLUDA, J.

RIV year

2018

Released

12.11.2017

ISBN

1478-6443

Periodical

PHILOSOPHICAL MAGAZINE

Volume

97

Number

32

State

United Kingdom of Great Britain and Northern Ireland

Pages from

2971

Pages to

2984

Pages count

14

BibTex

@article{BUT138181,
  author="Miroslav {Černý} and Petr {Řehák} and Jaroslav {Pokluda}",
  title="The origin of lattice instability in bcc tungsten under triaxial loading",
  journal="PHILOSOPHICAL MAGAZINE",
  year="2017",
  volume="97",
  number="32",
  pages="2971--2984",
  doi="10.1080/14786435.2017.1363424",
  issn="1478-6435"
}