Pressure dependence of structural, electronic, elastic and thermodynamic behaviors of AlY2: A first principles study

The AlY2 binary compound is important for the development of rare earth alloying Al based materials, but up to now there is no experimental and calculated data on the electronic, elastic and thermodynamic properties. In this work, first principles calculations have been carried out to analyze the structural stability and to determine the electric, elastic and thermodynamic properties of AlY2 as a function of pressure from 0 to 50 GPa with a step 5 GPa. For the sake of consistency, the approach of the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerh (PBE) was used. The results show that the calculated structural parameters of AlY2 are consistent with the experimental data. The result of band structure shows that AlY2 exhibits half-metallic conductivity and the form of DOS changes obviously when pressure increases. It is shown by the results of bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio v and Debye temperature ΘD using the Voigt–Reuss–Hill (VRH) averaging scheme that, AlY2 is mechanically stable and the primary parameter limiting the stability of compound is shear modulus. The value of B/G increases with increasing pressure, indicating that the ductility of AlY2 may be improved under high pressures. The Debye temperature also increases along with the pressure. The results indicate that external pressure has a little influence on the thermodynamic properties like heat capacity C, enthalpy E, free energy F and entropy S.