Phase stability, thermodynamic and mechanical properties of AlZr2, FeZr2 and Al2FeZr6 from first-principles calculations

The phase stability, thermodynamic and mechanical properties of AlZr2, FeZr2 and Al2FeZr6 have been investigated by using density functional theory (DFT). The calculated lattice constants and formation enthalpies of the three compounds are all in good agreement with experimental data and other available theoretical results. Using quasi-harmonic Debye model, Gibbs energies of the three compounds have been calculated and the calculated Gibbs energies show that the decomposition temperature of Al2FeZr6 decreases with increasing internal pressure. All of the calculated elastic constants of the considered compounds are satisfied with the mechanical stability conditions. The polycrystalline bulk modulus, shear modulus, Young's modulus and Poisson's ratio for the three compounds are obtained and discussed