On mechanical twinning in tetragonal lattice

0563902 - ÚFM 2024 RIV GB eng J - Článek v odborném periodiku
Zelený, M. - Ostapovets, Andriy - Fridrich, Lucius - Šesták, P. - Heczko, M. - Kruml, Tomáš
On mechanical twinning in tetragonal lattice.
Philosophical Magazine. Roč. 103, č. 2 (2023), s. 119-136. ISSN 1478-6435. E-ISSN 1478-6443
Institucionální podpora: RVO:68081723
Klíčová slova: Twinning * tetragonal lattice * phase transformations * intermetallic compounds
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 1.6, rok: 2022
Způsob publikování: Open access
https://www.tandfonline.com/doi/full/10.1080/14786435.2022.2135037

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.
Trvalý link: https://hdl.handle.net/11104/0341868