document: The thermodynamics of copper-zinc alloys (brass) was subject of numerous investigations. Brass is characterised by an excess enthalpy and excess entropy of mixing, both of which are negative. The enthalpic data were measured by solution calorimetry e.g., [1–3] and based on chemical potential data calculated from phase equilibrium experiments e.g., [4–6], the excess entropy of mixing could be evaluated e.g., [7–9]. This excess entropy contains both, the vibrational and the configurational parts. The excess vibrational entropy, defined as the deviation from the entropy of a mechanical mixture of the end members A and B (i.e., Smmechmix=XASmA+XBSmB), can be determined by measuring the low temperature heat capacity (5 to 300K) versus composition behaviour. The determination of the excess configurational entropy, i.e., the excess entropy coming from non-random atomic distributions and defects, is much more difficult. Here, neutron scattering investigations together with computer simulations are normally used. If, however, reliable data of the total excess entropy (from enthalpic and chemical potential data) are available, the measurement of the excess vibrational entropy enables the determination of the excess configurational entropy simply by subtraction. Since configurational and vibrational entropies may have different temperature dependencies, it is worthwhile to separate the entropic effects. This is one aim of this study. Another aim is to deliver experimental data so that first principles studies can test their models on a disordered alloy, whose structural details (short-range order) depend on temperature.
extractive_keyphrases: brass chemical potential data computer simulations deliver experimental data determination of the excess configurational entropy disordered alloy enthalpic data excess enthalpy and excess entropy of mixing excess entropy of mixing measurement of the excess vibrational entropy neutron scattering investigations phase equilibrium experiments reliable data of the total excess entropy separate the entropic effects solution calorimetry subtraction vibrational and the configurational parts
abstractive_keyphrases: copper-zinc alloys enthalpic and chemical potential data excess configurational entropy experimental data measuring the low temperature heat capacity (5 to 300k) versus composition behaviour smmechmix=xasma+xbsmb thermodynamics of copper-zinc alloys (brass)