First-principles investigation of the structural and elastic properties of Be12Ti under high pressure

Abstract

The effects of pressure on the structural and elastic properties of Be₁₂Ti were investigated by the generalized gradient approximation (GGA) with a Perdew–Burke–Ernzerhof (PBE) exchange-correlation function using density-functional theory. The calculated lattice parameters at zero pressure and zero temperature are in good agreement with the available experimental data. The pressure dependence of the normalized parameters a/a₀, c/c₀, V/V₀ and elastic constants was investigated and it was found that the elastic constants of Be₁₂Ti increase monotonically with increasing pressure. By the Born's elastic stability criteria, hexagonal (hcp) Be₁₂Ti is mechanically unstable at pressures greater than 41 GPa. The elastic properties such as bulk modulus (B), shear modulus (G), Young's modulus (E) and Poisson's ratio (v) under pressures ranging up to 44 GPa were calculated using the Voigt–Reuss–Hill method. The brittleness and plasticity of the Be₁₂Ti alloy were also determined. The Debye temperature and anisotropy under different pressures were also successfully estimated from the calculations.