The mechanical and thermodynamic properties of the tetragonal Mo5SiB2 and Mo5Si3 phase under high pressure: a first-principles study

Abstract

The mechanical and thermodynamics properties of Mo5Si3 and Mo5SiB2 have been investigated by using the first-principle calculations. The cell structure parameters with pressure are briefly discussed. The values of micro-hardness and melting point of both Mo5SiB2 and Mo5Si3 are studied. In addition, both composite alloys’ elastic constants Cij and elastic modulus (B, G, E) are close to increase linearly with pressure. The B/G ratios and Cauchy pressure (C12–C44) were also investigated by this method, and the results suggest that pressure can improve the ductility properties of both alloys. The Poisson’s ratio indicates that the two alloys are bonded mainly metallic. Finally, the Debye temperature with pressure concluded from elastic constants was studied, and the temperature dependence of thermodynamic properties, including the entropy, constant volume heat capacity (CV), enthalpy, and Gibbs free energy, are also studied and discussed.