Numerical Prediction of the Thermodynamic Properties of Ternary Al-Ni-Pd Alloys

Abstract

Thermodynamic properties of ternary Al-Ni-Pd system, such as exGAlNPd, μAl(AlNiPd), μNi(AlNiPd) and μPd(AlNiPd) at 1,373 K, were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting exGAlNiPd values was regarded as calculation of values of the exG function inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of exG on all legs of the triangle are known (exGAlNi, exGAlPd, exGNiPd). This approach is contrary to finding a function value outside a certain area, if the function value inside this area is known. exG and LAl,Ni,Pd ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism were calculated numerically using the Excel program and Solver. The accepted values of the third component xx differed from 0.01 to 0.1 mole fraction. Values of LAlNiPd parameters in the Redlich-Kister formula are different for different xx values, but values of thermodynamic functions: exGAlNiPd, μAl(AlNiPd), μNi(AlNiPd) and μPd(AlNiPd) do not differ significantly for different xx values. The choice of xx value does not influence the accuracy of calculations.