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Carbon in iron phases under high pressure
Author(s) -
Huang L.,
Skorodumova N. V.,
Belonoshko A. B.,
Johansson B.,
Ahuja R.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl024187
Subject(s) - carbide , materials science , carbon fibers , solubility , impurity , phase (matter) , high pressure , iron oxide , thermodynamics , analytical chemistry (journal) , metallurgy , chemistry , composite material , physics , organic chemistry , composite number , chromatography
The influence of carbon impurities on the properties of iron phases (bcc, hcp, dhcp, fcc) has been studied using the first‐principles projector augmented‐wave (PAW) method for a wide pressure range. It is shown that the presence of ∼6 at. % of interstitial carbon has a little effect on the calculated structural sequence of the iron phases under high pressure. The bcc → hcp transition both for pure iron and iron containing carbon takes place around 9 GPa. According to the enthalpies comparison, the solubility of carbon into the iron solid is decreased by high pressure. The coexistence of iron carbide (Fe 3 C) + pure hcp Fe is most stable phase at high pressure compared with other phases. Based on the analysis of the pressure‐density dependences for Fe 3 C and hcp Fe, we suggest that there might be some fraction of iron carbide present in the core.