<i>Ab-Initio</i> Study of Electronic Structure of Martensitic Twin Boundary in Ni₂MnGa Alloy

Abstract

The electronic structure of (110) and (011) martensitic twin boundary in Ni 2 MnGa alloys has been calculated by using ab initio method within the density-functional theory (DFT) and the supercell implementation. The calculated results show that the energy for the (110) twin boundary is larger than that for another twin due to their difference in the chemical decomposition and crystal structure. The atomic relaxation lowers the interface energies for both (110) and (011) twins and this kind of energy is still positive after relaxation. The structural stability and the magnetic properties of the twining interface are investigated and compared with each other from the total and spin density of states under atom-relaxation and -unrelaxation. The atoms such as Ni and Mn have different magnetic moments in the two kinds of twin boundaries. The total charge density on the plane passing through the twin plane gives the direct explanations of the bonding between atoms.

Grain Boundary Segregation in Pd-Cu-Ag Alloys for High Permeability Hydrogen Separation Membranes

“…Several DFT studies have investigated GB segregation in metals, e.g., in Ni [ 31 ], Ti [ 32 ], and Fe [ 33 ]. Other studies have focused on studying GB energies in alloys, e.g., in NiTi [ 34 ], Ti-Mo and Ti-V alloys [ 35 ], and in the ternary Ni 2 MnGa [ 36 ], and Ni-Al-Co systems [ 37 ]. Some studies have also investigated GB segregation in alloys, e.g., in Cu-Ag [ 38 ], various binary V alloys [ 39 ], and in the ternary Mg-Zn-Y [ 40 ] and FeCrNi [ 41 ] alloys.…”