First-Principles Study of Electronic Structure and Elastic Properties of Si Doping Ti3Al1-xSixC2 Solid Solutions

摘要

The electronic structure and elastic properties of Si doping Ti3Al1-xSixC2 (x=0-1) were studied by generalized gradient approximation (GGA) based on density functional theory (DFT) and virtual crystal approximation (VCA).The calculated lattice parameters and equilibrium volumes are in good agreement with the available experimental data.The density of state (DOS) shows that the DOS at the Fermi level (EF) is located at the bottom of a valley.Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt,Reuss and Hill's approximations (VRH).The results show that the bulk modules increase monotonously and the Poisson ratio v as well as BH and BG increase first and then decrease with the increasing of the doping Si.The Passion ratio v and BH/GH indicate that Ti3Al1-xSixC2 (x=0-1) are brittle compounds.Polycrystalline elastic anisotropy coefficients AB and AG were also derived and are very small.