Pre-melting <i>hcp </i>to <i>bcc </i>Transition in Beryllium
ORAL
Abstract
Beryllium (Be) is an important material with wide applications ranging from aerospace components to x-ray ray equipment. Yet a precise understanding of its phase diagram remains elusive. We have investigated the phase stability of Be using a recently developed hybrid free-energy computation method that accounts for anharmonic effects by invoking phonon quasiparticles. We find that the hcp → bcc transition occurs near the melting curve at 0 < P < 11 GPa with a positive Clapeyron slope of 41(4) K/GPa, a result that is more consistent with recent experimental measurements. This work also demonstrates the validity of this theoretical framework based on the phonon gas model and phonon quasiparticle to study phase transitions in strongly anharmonic materials.
*DBZ, was supported by NSFC grants U1530401, 41474069 and 11328401, and NSAF Grant No. U1530258. RW was supported by NSF grants EAR-1341862 and -1348066. PZ was supported by NSF grant DMR-1506669.
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Presenters
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Renata Wentzcovitch
- Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University
- Applied Physics and Mathematics, Columbia University
- Columbia Univ
- Applied Physics and Applied Mathematics, Columbia University
- Columbia University
- Department of Applied Physics and Applied Mathematics, Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University