Thermodynamic properties of metastable Ag-Cu alloys

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Abstract
Copyright 1993 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The article originally appeared in Journal of Applied Physics 74, 3144 (1993) and may be found at http://jap.aip.org/resource/1/japiau/v74/i5/p3144_s1.The enthalpies of formation of metastable fcc Ag‐Cu solid solutions, produced by ball milling of elemental powders, were determined by differential scanning calorimetry. Experimental thermodynamic data for these metastable alloys and for the equilibrium phases are compared with both calculation of phase diagrams (CALPHAD) and atomistic simulation predictions. The atomistic simulations were performed using the free‐energy minimization method (FEMM). The FEMM determination of the equilibrium Ag‐Cu phase diagram and the enthalpy of formation and lattice parameters of the metastable solid solutions are in good agreement with the experimental measurements. CALPHAD calculations made in the same metastable regime, however, significantly overestimate the enthalpy of formation. Thus, the FEMM is a viable alternative approach for the calculation of thermodynamic properties of equilibrium and metastable phases, provided reliable interatomic potentials are available. The FEMM is also capable of determining such properties as the lattice parameter which are not available from CALPHAD calculations.