Philip J. Spencer

Estimation of thermodynamic data for metallurgical applications

The ever growing need to develop new materials for specific applications is leading to increased demand for thermodynamic values which have not been measured so far. This necessitates the use of estimated values for evaluating the feasibility or suitability of different proposed processes for producing materials with particular compositions and properties. Methods for estimating thermodynamic properties of inorganic and metallic substances are presented in this paper. A general categorization into estimation methods for heat capacities, entropies and enthalpies of formation has been used. Some comparisons of estimated values with experimental data are presented and possible future developments in estimation techniques are discussed.

A critical thermodynamic evaluation of the systems SiZn and AlSiZn

Abstract Thermodynamic evaluations of the systems SiZn and AlSiZn are presented. In the evaluation of the system AlSiZn, use is made of available thermodynamic evaluations of the binary subsystems. The results of the calculations are compared with published experimental data and cover a temperature range of 400–1700 K. In these calculations, the vapour phase has been included. It is shown that the thermodynamic behaviour of the three elements can be explained by a summation of binary interactions between the elements. The calculations in the ternary system are performed using “Txy-Calc”. A short outline of the “two dimensional phase mapping” method used in this program is given.

A critical thermodynamic evaluation of the system MG-NI

Abstract Within the framework of COST Action 507 a critical thermodynamic analysis has been carried out of the system Mg-Ni. All thermodynamic data obtained in this action and existing data reported in the literature are described by the thermodynamic analysis. This thermodynamic evaluation is valid between 300 K and 1728 K (the melting temperature of Ni) and for the complete composition range. The purpose of the evaluation is to establish a firm basis for the thermodynamic description of the ternary system Cu-Mg-Ni.

Thermodynamic assessments of the Cu-Pb-Zn and Cu-Sn-Zn systems

Abstract Thermodynamic assessments of the Cu-Sn-Zn and Cu-Pb-Zn systems are presented. For this work the evaluations of the binary Cu-Zn, Cu-Pb, Sn-Zn and Pb-Zn subsystems have been taken from the SGTE database [86Ans], for the Cu-Sn system the data [96Shi] were used. The results of phase equilibrium calculations in the ternary systems are shown in appropriate diagrams and tables and compared with published experimental data.

Evaluation of the phase diagram and thermochemistry of the CU-Y system

Abstract Experimental information on the phase equilibria and thermochemistry of the Cu-Y system were combined with the help of a computer optimization program to achieve a self-consistent analytical description of the thermodynamic properties of Cu-Y alloys. The resulting set of coefficients allows calculation of thermodynamic functions for the pure components, stoichiometric phases or solution phases in the system, as well as calculation of the equilibria between the phases.

A THERMODYNAMIC EVALUATION OF THE IRON-ZINC SYSTEM

Experimental thermodynamic properties and phase equilibrium data have been used in deriving a thermodynamically consistent analytical description of the thermochemical properties and phase diagram of the Fe-Zn system. A set of coefficients is used to describe the conventional Gibbs free energy of the pure components and stoichiometric intermetallic compounds and the excess Gibbs energies of the solution phases are given. Thermodynamic and phase boundary values calculated with these coefficients agree well with experimental data within experimental error.

A thermodynamic evaluation of the copper-phosphorus system

Abstract A critical thermodynamic evaluation of available, experimental information for the system Cu-P has been carried out. The representation of measured data by optimised coefficients of a polynomial function in composition and temperature leads to an analytical description of the thermodynamic properties of Cu-P, which allows both thermodynamic functions or phase equilibria for the system to be calculated. The extent of the agreement between calculated and measured properties is discussed.

A thermodynamic evaluation of the Ba-Cu-Y System

Abstract Experimental thermodynamic and phase equilibrium measurements in the binary systems Ba-Cu, Ba-Y and Cu-Y, together with experimental information on the miscibility gap in the ternary system Ba-Cu-Y, have been evaluated with the aid of the ‘Lukas optimization program’. The resulting set of coefficients allow phase equilibria and thermodynamic values to be reproduced within satisfactory limits.

A cluster expansion for Cu-Au alloys based on experimental data

Abstract The calculation of effective cluster interactions (ECIs) from experimental data rather than from calculated total energies is described. The procedure is illustrated for Cu-Au alloys with the enthalpy of mixing for random alloys being calculated from experimental data for the ordered alloys. The cluster expansion formalism from which the ECIs are obtained could direct the conventional thermodynamic evaluation of phase diagrams to a physically more fundamentel viewpoint and, consequently, become an important new component to be considered in the CALPHAD-like assessments.