Thermodynamic functions of aluminum in the solid state

Taking account of the influence of anharmonic effects, which are expressed in an explicit temperature dependence of the characteristic Debye temperatu re theta(T), a systematic thermodynamic analysis of the interpolation formu las used for the analysis of high-temperature measures of the thermodynamic properties of solids is undertaken, The physical meaning of the empirical interpolation coefficients is determined. Expressions are given for the the rmodynamic potential, enthalpy, specific heat, and entropy. For the example of aluminum, it is shown that the proposed approach ensures good agreement of the experimental and calculation results over the whole solid state of the metal, except in the vicinity of the melting point. The discrepancy bet ween the experimental and theoretical specific-heat values close to the mel ting point may be interpreted on the basis of the Frenkel vacancy model, Go od agreement of the theoretical and experimental thermodynamic data right u p to the melting point is obtained for aluminum if the influence of both an harmonic effects and premelting processes is taken into account.