Nanotwinning and Modulation of Martensitic Structures in Ni2MnGa Alloy: An ab initio Study
M. Zelený
Institute of Materials Science and Engineering, NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, CZ-61669 Brno, Czech Republic
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The ab initio electronic structure calculations show importance of nanotwinning concept for understanding martensitic lattice geometry in Ni2MnGa magnetic shape memory alloys. All modulated martensitic structures, 4O, 10M and 14M, are stabilized due to the presence of nanotwin double layers in the structure, i.e., nanotwins consisting of two (101) lattice planes of nonmodulated martensitic structure. In all structures, the most significant decrease of total energy arises from a shift of Mn and Ga atoms at the nanotwin boundaries by about 1% of atomic coordinate.

DOI:10.12693/APhysPolA.134.658
PACS numbers: 62.20.fg, 31.15.es, 61.66.-f