First-principles investigations of elastic, electronic and thermodynamic properties of Al12X (X = Mo, W and Re)

The mechanical, electronic and thermodynamic properties of Al12X (X = Mo, W, Re) compounds are investigated by means of density functional theory (DFT) based calculations. The calculated lattice constants of the compounds are in good agreement with the experimental data. Compared with the other theoretical data, the calculated formation enthalpy of Al12Mo is very accurate. The elastic constants of the three compounds have been calculated, and the bulk modulus, shear modulus, and Young’s modulus have been evaluated. The calculated results indicated that all three compounds show brittle behavior. The electronic density of states (DOS) and the bonding charge density have also been calculated to elucidate the bonding mechanism in these compounds and the results indicate that bonding characteristic is mostly of covalent nature. Finally, using a quasiharmonic Debye model, the Debye temperature, the heat capacity, the coefficient of thermal expansion and the Grüneisen parameter have also been obtained in the present work. The present calculations show that the Al12X (Mo, W and Re) intermetallics can enhance mechanical properties of the Al-matrix dramatically.