In-situ X-ray diffraction measurements of the [gamma-epsilon] transition boundary of iron in an internally-heated diamond anvil cell

Journal Article · Thu May 07 04:00:00 EDT 2009 · Earth Planet. Sci. Lett.

DOI:https://doi.org/10.1016/j.epsl.2009.03.025· OSTI ID:1005595

Komabayashi, T; Fei, Y; Meng, Y; Prakapenka, V

The phase transition boundary between the {gamma} (face-centered cubic structure) and {epsilon} (hexagonal close-packed structure) iron phases was determined up to 69 GPa by using a newly developed internally-heated diamond anvil cell, combined with in-situ synchrotron X-ray diffraction measurements. The improved experimental configuration provides stable heating with reliable temperature and pressure determination and phase identification. A simultaneous laser- and internal-heating system was also used to produce further higher temperature at higher pressures. The sample pressure at any given temperature was calculated using an established thermal equation of state for {epsilon} iron. The {gamma}-{epsilon} transition boundary was bracketed with the normal and reversal directions and it is linear from 21 to 69 GPa with a dP/dT slope of 0.0394 GPa/K. There is no evidence for the existence of additional iron solid phase other than the {gamma} and {epsilon} phases over the P-T range of this study. We inferred that the {gamma}-{epsilon}-liquid triple point of iron should occur at 88 GPa and 2800 K.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE
• OSTI ID: 1005595
• Journal Information: Earth Planet. Sci. Lett., Journal Name: Earth Planet. Sci. Lett. Journal Issue: (1-4) ; 05, 2009 Vol. 282; ISSN 0012-821X; ISSN EPSLA2
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
CRYSTAL-PHASE TRANSFORMATIONS
EQUATIONS OF STATE
FCC LATTICES
HCP LATTICES
IRON
PRESSURE RANGE GIGA PA
TEMPERATURE RANGE 1000-4000 K
TRIPLE POINT
X-RAY DIFFRACTION