Publication detail

On energetics of allotrope transformations in transition-metal diborides via plane-by-plane shearing

LEINER, T. KOUTNÁ, N. JANOVEC, J. ZELENÝ, M. MAYRHOFER, P. HOLEC, D.

English title

On energetics of allotrope transformations in transition-metal diborides via plane-by-plane shearing

Type

journal article in Web of Science

Language

en

Original abstract

Transition metal diborides crystallize in the a, y, or w type structure, in which pure transition metal layers alternate with pure boron layers stacked along the hexagonal [0001] axis. Here we view the prototypes as different stackings of the transition metal planes and suppose they can transform from one into another by a displacive transformation. Employing first-principles calculations, we simulate sliding of individual planes in the group IV-VII transition metal diborides along a transformation pathway connecting the a, y, and w structure. Chemistry-related trends are predicted in terms of energetic and structural changes along a transformation pathway, together with the mechanical and dynamical stability of the different stackings. Our results suggest that MnB2 and MoB2 possess the overall lowest sliding barriers among the investigated TMB2s. Furthermore, we discuss trends in strength and ductility indicators, including Young's modulus or Cauchy pressure, derived from elastic constants.

English abstract

Transition metal diborides crystallize in the a, y, or w type structure, in which pure transition metal layers alternate with pure boron layers stacked along the hexagonal [0001] axis. Here we view the prototypes as different stackings of the transition metal planes and suppose they can transform from one into another by a displacive transformation. Employing first-principles calculations, we simulate sliding of individual planes in the group IV-VII transition metal diborides along a transformation pathway connecting the a, y, and w structure. Chemistry-related trends are predicted in terms of energetic and structural changes along a transformation pathway, together with the mechanical and dynamical stability of the different stackings. Our results suggest that MnB2 and MoB2 possess the overall lowest sliding barriers among the investigated TMB2s. Furthermore, we discuss trends in strength and ductility indicators, including Young's modulus or Cauchy pressure, derived from elastic constants.

Keywords in English

Ab initio calculations; Transition metal diborides; Shear; Stacking sequence; Phase stability

Released

29.06.2023

Publisher

Elsevier

Location

OXFORD

ISSN

1879-2715

Volume

215

Number

1

Pages from–to

112329–-

Pages count

9

BIBTEX


@article{BUT184357,
  author="Thomas {Leiner} and Nikola {Koutná} and Jozef {Janovec} and Martin {Zelený} and Paul {Mayrhofer} and David {Holec},
  title="On energetics of allotrope transformations in transition-metal diborides via plane-by-plane shearing",
  year="2023",
  volume="215",
  number="1",
  month="June",
  pages="112329---",
  publisher="Elsevier",
  address="OXFORD",
  issn="1879-2715"
}