Electronic Structures, Elastic and Anisotropic Properties of Tial3 Intermetallics Doped with Nb

Abstract

The elastic and anisotropic properties of TiAl3 intermetallics doped with Nb are investigated systematically based on the electronic structures calculation. It shows that the Nb atoms are preferentially to substitute Ti sites forming a stable crystal structure. The DOS of Nb–doped TiAl3 suggests that there is a pseudogap in (Ti18–x+Nbx)Al54. It reinforces atomic covalent bonds while the metallic bond in Ti18(Al54–x+Nbx) is increased. The predicted elastic properties of Nb–doped TiAl3 implied that its strength can be reinforced when the Ti sites substituted by Nb whereas the ductility of the doped intermetallics can be ameliorated when Al sites substituted by Nb. The anisotropy of Young’s modulus and shear modulus indicate the uniform deformation ability of (Ti18–x+Nbx)Al54 is better than that of Ti18(Al54–x+Nbx). Poisson’s ratio of Ti18Al54 and Ti18(Al51+Nb3) suggest an auxetic feature may be existed when a tensile stress is applied on a specific direction.

Keywords: TiAl3, Nb-doping, electronic structure, Elastic properties, Anisotropy