Publication detail

On mechanical twinning in tetragonal lattice

ZELENÝ, M. OSTAPOVETS, A. FRIDRICH, L. ŠESTÁK, P. HECZKO, M. KRUML, T.

English title

On mechanical twinning in tetragonal lattice

Type

journal article in Web of Science

Language

en

Original abstract

The theory of mechanical twinning is revisited for the case of face-centred tetragonal lattices. The motivation is an imprecision in the determination of twinning shear vector magnitude, which occurs repeatedly in the literature. The magnitude of this vector describing the mutual shear of two adjacent crystallographic planes in the process of twin formation is a function of the tetragonality of the lattice c/a. Therefore, we introduce the c/a-dependent factor f which has to be applied to the magnitude of shearing vector < 112] instead of the commonly use factor 1/6, which is correct only for perfect cubic lattices. The theory is verified by ab initio calculations of the generalised planar fault energy curves for three tetragonal materials: the nonmodulated martensite phase of Ni2FeGa magnetic shape memory alloy,.-TiAl intermetallic and pure In. Moreover, the calculations show that the additional modification of shear vector is caused by structural optimisation due to short-range interactions in the vicinity of twin interface, especially for lattices with large deviation of c/a from 1. Such modification cannot be simply predicted from the lattice geometry.

English abstract

The theory of mechanical twinning is revisited for the case of face-centred tetragonal lattices. The motivation is an imprecision in the determination of twinning shear vector magnitude, which occurs repeatedly in the literature. The magnitude of this vector describing the mutual shear of two adjacent crystallographic planes in the process of twin formation is a function of the tetragonality of the lattice c/a. Therefore, we introduce the c/a-dependent factor f which has to be applied to the magnitude of shearing vector < 112] instead of the commonly use factor 1/6, which is correct only for perfect cubic lattices. The theory is verified by ab initio calculations of the generalised planar fault energy curves for three tetragonal materials: the nonmodulated martensite phase of Ni2FeGa magnetic shape memory alloy,.-TiAl intermetallic and pure In. Moreover, the calculations show that the additional modification of shear vector is caused by structural optimisation due to short-range interactions in the vicinity of twin interface, especially for lattices with large deviation of c/a from 1. Such modification cannot be simply predicted from the lattice geometry.

Keywords in English

Twinning; tetragonal lattice; phase transformations; intermetallic compounds

Released

27.10.2022

Publisher

TAYLOR & FRANCIS LTD

Location

ABINGDON

ISSN

1478-6443

Volume

103

Number

2

Pages from–to

119–136

Pages count

18

BIBTEX


@article{BUT181519,
  author="Martin {Zelený} and Andriy {Ostapovets} and Lucius {Fridrich} and Petr {Šesták} and Martin {Heczko} and Tomáš {Kruml},
  title="On mechanical twinning in tetragonal lattice",
  year="2022",
  volume="103",
  number="2",
  month="October",
  pages="119--136",
  publisher="TAYLOR & FRANCIS LTD",
  address="ABINGDON",
  issn="1478-6443"
}