First-principles calculations to investigate structural, electronic, elastic and thermal properties of Mg doped Ti2Ni intermetallics

The electronic, elastic and thermal properties of Mg doped Ti2Ni intermetallics are predicted based on DFT theory. The results show that Ti site is preferentially substituted by Mg atoms and a resonance effect occurs between Mg-2p and Ti-3d orbitals, causing the TDOS peak near Fermi level to split with dopant concentration increasing, resulting in the strength increases and ductility decreases correspondingly. The elastic constants indicated that the bulk, shear and Young's modulus of doped compound are lower than that of the undoped ones. The BH/GH ratio of doped system is greater than 1.75 and the Poisson's ratio is above 0.26. Comparatively, the (Ti64-x + Mgx)Ni32 exhibits greater elastic strength than that of Ti64(Ni32-x + Mgx). Doping leads to a relatively lower covalent character in Ti64(Ni32-x + Mgx) and stronger bonding capability in (Ti64-x + Mgx)Ni32, resulting in a significant changes in modulus. Consequently, the Debye temperature of the (Ti64-x + Mgx)Ni32 is higher than that of the Ti64(Ni32-x + Mgx).