Theoretical study of concentration and size dependencies of the properties of Mo–W alloy

Based on the parameters of the pair potential of the Mie – Lennard-Jones interatomic interaction for Mo and W and using the “average atom” method, the properties of the Mo–W substitutional alloy were calculated. Isobaric concentration dependencies were obtained for the interatomic distance, Debye temperature, Grüneisen parameter, modulus, thermal expansion coefficient, and surface energy along various isotherms. The calculated dependencies showed good agreement with the experimental data available in the literature. Using the RP-model of a nanocrystal, for the first time, size dependencies were obtained both for the equation of state and for various properties of an alloy of equiatomic composition Mo0.5-W0.5: elastic modulus, thermal expansion coefficient, isobaric heat capacity, surface energy, and surface energy derivative with respect to temperature. Calculations of the size dependencies of these properties were performed both along different isotherms and along different isobars. We calculated both the size dependencies at constant temperature and pressure and the temperature dependencies of the properties at constant values of pressure and number of atoms in the nanocrystal. [Display omitted] •Phase diagram of Mo–W alloy has been calculated.•Equation of state for both macro and nanocrystal of Mo–W alloy.•Concentration dependencies of properties of Mo–W alloy have been obtained.•Size dependencies of the properties of Mo–W nanocrystal at different P-T-conditions.•Size and temperature dependencies of surface energy for Mo–W alloy at different P-T-conditions have been studied.