Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 60: Microstructure and Phase Transformations III

MM 60.2: Vortrag

Donnerstag, 10. März 2016, 16:00–16:15, H39

First-principle study of phase transformations in Ni₂MnGa alloy — •Martin Zeleny^1,2, Alexei Sozinov³, Ladislav Straka⁴, and Oleg Heczko⁵ — ¹Institute of Materials Science and Engineering, NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology, Brno, Czech Republic — ²Central European Institute of Technology, CEITEC MU, Masaryk University, Brno, Czech Republic — ³Material Physics Laboratory, Lappeenranta University of Technology, Savonlinna, Finland — ⁴Aalto University School of Engineering, Laboratory of Engineering Materials, Aalto, Finland — ⁵Institute of Physics of Academy of Sciences of the Czech Republic, Prague, Czech Republic

Transformation path between different phases of Ni₂MnGa alloy has been investigated using first-principle electronic structure calculations. We used the projector-augmented wave method for the calculations of total energies and stresses along the transformation paths. These include transformation from austenite (A) to nonmodulated tetragonal martensite (NM), transformation from modulated martensites (10 M and 14 M) to NM martensite, as well as transformation between adjacent twin variants of NM phase. All transformations are induced by applying external shear strain. The results show the same barrier equal to 0.4 mRy/atom for A→NM transformation, 10M→NM transformation and NM twin reorientation whereas 14M→NM transformation exhibits smaller barrier equal to 0.25 mRy/atom. Calculated lower barrier well corresponds to experimental finding that the transformation from 10M to NM always proceeds via intermediate 14M phase.