Revealing the stability, elastic properties and electronic structures of Pd-V intermetallics via first principle calculations

Abstract

Precious metals and their alloys are promising high-temperature materials due to the high melting point, high strength and thermodynamically stability, in which Pd-V alloys are one kind of important systems. However, the influence of V concentration on structure stability, mechanical and thermodynamic properties and chemical bonding of Pd-V compounds is unknown. The structures, elastic properties, anisotropic of elastic and electronic structures of thirteen Pd-V compounds as a function of V concentration have been investigated by first principle calculations in this work. We have determined all the possible stable phases of Pd-V system for the first time by thermodynamics convex hull and phonon spectrum. The calculated results show that α-Pd2V has the lowest formation enthalpies as -0.34 eV/atom, indicating more thermodynamically stable than other structures. The elastic constants, bulk modulus, shear modulus, Young's modulus and Poisson's ratio of the Pd-V compounds are also calculated and the β-Pd3V has the largest shear modulus and Young's modulus as 107.1 GPa and 275.7 GPa, respectively. The anisotropic mechanical properties of these Pd-V compounds are discussed in detailed by the anisotropic index, three-dimensional (3D) surface contours and the planer projections on (001) and (110) planes of the Young's modulus. The values of total density of states (TDOS) of all compounds are nonzero at Fermi energy (EF), indicating metallic feature for all the Pd-V compounds.