Elastic properties of mono- and polycrystalline hexagonal AlB2-like diborides of s, p and d metals from first-principles calculations

TL;DR

This study uses first-principles calculations to systematically analyze the elastic properties of 18 hexagonal AlB2-like metal diborides, providing new data on their elastic constants and related parameters for both mono- and polycrystalline forms.

Contribution

It offers the first numerical estimates of elastic parameters for polycrystalline MB2 ceramics using ab initio methods, expanding understanding of their mechanical properties.

Findings

Elastic constants and lattice parameters are calculated for 18 MB2 compounds.

Polycrystalline elastic parameters such as bulk and shear modules are estimated.

Results are compared with existing theoretical and experimental data.

Abstract

We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 18 stable, meta-stable and hypothetical hexagonal (AlB2-like) metal diborides MB2, where M = Na, Be, Mg, Ca, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ag and Au. For monocrystalline MB2 the optimized lattice parameters, independent elastic constants (Cij), bulk modules (B), shear modules (G) are obtained and analyzed in comparison with the available theoretical and experimental data. For the first time numerical estimates of a set of elastic parameters of the polycrystalline MB2 ceramics (in the framework of the Voigt-Reuss-Hill approximation), namely bulk and shear modules, compressibility, Young's modules, Poisson's ratio, Lame's coefficients are performed.