| About this Abstract |
| Meeting |
2016 TMS Annual Meeting & Exhibition
|
| Symposium
|
Hume-Rothery Award Symposium: Thermodynamics of Materials
|
| Presentation Title |
Electronic Structure and Phonon Thermodynamics of Fe-Au Alloys |
| Author(s) |
Jorge Munoz, Matthew Lucas, Lisa Mauger, Brent Fultz |
| On-Site Speaker (Planned) |
Jorge Munoz |
| Abstract Scope |
We present measurements of the phonon spectra of several Au-rich alloys of face-centered-cubic Fe-Au acquired using inelastic neutron scattering and nuclear-resonant inelastic x-ray scattering. Force constants were calculated from first principles for several compositions and show a local stiffening of the bonds between Au atoms when close to a Fe atom, and this stiffening is commensurate with the charge transfer from the Fe to the Au atoms upon alloying. A modified Wills-Harrison model that accounts for charge transfer is used to explain the observed negative excess vibrational entropy of mixing, which increases the miscibility gap temperature in the system by an estimated maximum of 550 K and we adjudicate to an increase in the electron density in the free-electron-like states and stronger sd-hybridization that results from the charge transfer. |
| Proceedings Inclusion? |
Planned: A print-only volume |