Dynamical stability of iron under high-temperature and high-pressure conditions
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University - 800 Dongchuan Road, Minhang, Shanghai 200240, China
Accepted: 8 February 2012
The dynamical stability of iron under high-temperature and high-pressure conditions was investigated based on the phonons evaluated by using a recently developed method. It is revealed that both the fcc-Fe and the hcp-Fe are dynamically stable in a wide temperature and pressure range. The bcc-Fe phase can be stable as well, while in a limited temperature/pressure regime bounded by a dynamical stability limit and a harmonic limit. Direct evidence shows that it is the entropy term that plays a critical role in stabilizing the bcc-Fe under high-temperature and high-pressure conditions.
PACS: 63.20.-e – Phonons in crystal lattices / 62.50.-p – High-pressure effects in solids and liquids / 91.35.Lj – Composition and state of the Earth's interior
© EPLA, 2012