Regensburg 2016 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 60: Microstructure and Phase Transformations III
MM 60.2: Talk
Thursday, March 10, 2016, 16:00–16:15, H39
First-principle study of phase transformations in Ni2MnGa alloy — •Martin Zeleny1,2, 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.