Ab initio study of Ni2MnGa under shear deformation

Ab initio study of Ni2MnGa under shear deformation

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The effect of shear deformation on Ni2MnGa magnetic shape memory alloy has been investigated using ab initio electronic structure calculations. We used the projector-augmented wave method for the calculations of total energies and stresses as functions of applied affine shear deformation. The studied nonmodulated martensite (NM) phase exhibits a tetragonally distorted L21 structure with c/a > 1. A large strain corresponding to simple shears in <100>{001}, <001>{100} and <010>{100} systems was applied to describe a full path between two equivalent NM lattices. We also studied <10-1>{101} shear which is related to twining of NM phase. Twin reorientation in this system is possible, because applied positive shear results in path with significantly smaller energetic barrier than for negative shear and for shears in other studied systems. When the full relaxation of lattice parameters is allowed, the barriers further strongly decrease and the structures along the twinning path can be considered as orthorhombic.

The effect of shear deformation on Ni2MnGa magnetic shape memory alloy has been investigated using ab initio electronic structure calculations. We used the projector-augmented wave method for the calculations of total energies and stresses as functions of applied affine shear deformation. The studied nonmodulated martensite (NM) phase exhibits a tetragonally distorted L21 structure with c/a > 1. A large strain corresponding to simple shears in <100>{001}, <001>{100} and <010>{100} systems was applied to describe a full path between two equivalent NM lattices. We also studied <10-1>{101} shear which is related to twining of NM phase. Twin reorientation in this system is possible, because applied positive shear results in path with significantly smaller energetic barrier than for negative shear and for shears in other studied systems. When the full relaxation of lattice parameters is allowed, the barriers further strongly decrease and the structures along the twinning path can be considered as orthorhombic.

Magnetic shape memory alloys; martensitic phase transitions; shear deformation; ab initio calculations;

Magnetic shape memory alloys; martensitic phase transitions; shear deformation; ab initio calculations;

ZELENÝ, M.; STRAKA, L.; SOZINOV, A.

2016

07.12.2015

EDP Sciences

978-2-7598-1925-6

ESOMAT 2015 – 10th European Symposium on Martensitic Transformations

2261-236X

MATEC web of conferences

33

Francouzská republika

05006-1

05006-6

6

http://www.esomat.org/articles/matecconf/abs/2015/14/matecconf_esomat2015_05006/matecconf_esomat2015_05006.html

http://hdl.handle.net/11012/201033

matecconf_esomat2015_05006