title: The vibrational and configurational entropy of α-brass.
abstract: The heat capacities of two samples of a fcc Cu-Zn alloy with the composition CuZn15 and CuZn34 were measured fromT= 5 K to 573 K using relaxation and differential scanning calorimetry. Below ∼90 K, they are characterised by negative excess heat capacities deviating from ideal mixing by up to -0.20 and -0.44 J · mol-1· K-1for CuZn15 and CuZn34, respectively. The excess heat capacities produce excess vibrational entropies, which are less negative compared to the excess entropy available from the literature. Since the literature entropy data contain both, the configurational and the vibrational part of the entropy, the difference is attributed to the excess configurational entropy. The thermodynamics of different short-range ordered samples was also investigated. The extent of the short-range order had no influence on the heat capacity belowT= 300 K. AboveT= 300 K, where the ordering changed during the measurement, the heat capacity depended strongly on the thermal history of the samples. From these data, the heat and entropy of ordering was calculated. The results on the vibrational entropy of this study were also used to test a relationship for estimating the excess vibrational entropy of mixing.
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Artur
authors.initials: A
authors.lastname: Benisek
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Edgar
authors.initials: E
authors.lastname: Dachs
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Miralem
authors.initials: M
authors.lastname: Salihović
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Paunovic
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Maier
keywords: Calorimetry; Computer simulations; Excess configurational entropy; Excess heat capacity; Excess vibrational entropy; Fcc Cu–Zn alloy