Thermal expansion for ordered Cu3Au alloy at higher temperature and under pressure.

Abstract

Abstract The thermodynamic properties of alloys are studied using the statistical moment method (SMM), which allows us to take into account the anharmonicity of the thermal lattice vibration. Within the forth-order moment approximation, the free energy, equation of state and lattice spacing of the binary ordered alloys with cubic structure are given explicitly in terms of the effective pair potentials and the second - and fourth - order vibrational coefficients. Applying to ordered Cu 3 Au alloy, we determine these properties at higher temperature and under pressure in simple analytic form. Numerical results for the lattice parameter, pressure-volume dependence of this alloy in different temperatures and pressures are in good agreement with experiments, better than other calculations.