First-principles calculations of the elastic, phonon and thermodynamic properties of Al12Mg17

The elastic, phonon and thermodynamic properties of Al12Mg17 have been investigated by first-principles calculations. The obtained structural parameters, phonon dispersion curves and the predicted thermodynamic properties for all the phases studied herein agree well with available experimental data. The temperature-dependent single-crystal elastic constants are also predicted along with the polycrystalline aggregate properties, including bulk modulus, shear modulus, Young's modulus, and Poisson's ratio. The brittleness of Al12Mg17 that we predict is consistent with experiments, in contrast to the previous calculation showing ductile behavior. Detailed analysis of density of states further explains the present theoretical findings. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.