Theoretical study of elastic and electronic properties of Al5Mo and Al5W intermetallics under pressure

This work investigated the elastic and electronic properties of hexagonal Al5Mo and Al5W intermetallics using the first-principle method. In both phases, the structural, elastic and electronic properties showed the substantial pressure dependent behaviors. For formation enthalpies, they were both negative to indicate their stability at the ground state thermodynamically. In comparison, Al5Mo has the superior stability over Al5W owing to its more negative Hi. Elastically, the calculated elastic constants can satisfy Born's criteria from 0 to 40 GPa, suggesting their mechanical stability. With the increasing pressures, the elastic constants exhibited linearly rising tendencies. Using elastic constants, the bulk modulus (B), shear modulus (G) and Young's modulus (E) were derived using the Voigt-Reuss-Hill method. All these moduli displayed the increasing behaviors with the growing pressures. The analysis of BAG ratio and Poisson's ratio indicated that the Al5Mo and Al5W should be brittle at 0-40 GPa. Electronically, both compounds were suggested to possess metallic behavior through the DOS (density of states) analysis. Under pressures, the shapes of peaks and pseudogaps showed few changes, suggesting Al5Mo and Al5W has kept structurally stable up to 40 GPa. (C) 2017 Elsevier B.V. All rights reserved.