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Phonon entropy of alloying and ordering of Cu-Au

Bogdanoff, P. D. and Swan-Wood, T. L. and Fultz, B. (2003) Phonon entropy of alloying and ordering of Cu-Au. Physical Review B, 68 (1). Art. No. 014301. ISSN 0163-1829. http://resolver.caltech.edu/CaltechAUTHORS:BOGprb03

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Abstract

Inelastic neutron scattering spectra were measured with a time-of-flight spectrometer on six disordered Cu-Au alloys at 300 K. The neutron-weighted phonon density of states was obtained from a conventional analysis of these spectra. Several methods were developed to account for this neutron weighting and obtain the phonon entropy of the disordered alloys. The phonon entropies of formation of disordered fcc Cu-Au alloys obtained in this way were generally mutually consistent, and were also consistent with predictions from a cluster approximation obtained from ab-initio calculations by Ozolin[underaccent cedilla [below] s-breve, Wolverton, and Zunger. We estimate a phonon entropy of disordering of 0.15±0.05kB/atom in Cu3Au at 300 K. A resonance mode associated with the motions of the heavy Au atoms in the Cu-rich alloys was observed at 9 meV. An analysis of the resonance mode provided a check on the partial phonon entropy of Au atoms.


Item Type:Article
Additional Information:©2003 The American Physical Society (Received 20 January 2003; published 11 July 2003) This work was supported by the U.S. Department of Energy under Contract Nos. DE-FG03-96ER45572 and BES-MS, W-31-109-ENG-38.
Subject Keywords:copper alloys; gold alloys; phonons; order-disorder transformations; neutron diffraction; entropy
Record Number:CaltechAUTHORS:BOGprb03
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:BOGprb03
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.68.014301
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2904
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:05 May 2006
Last Modified:26 Dec 2012 08:51

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