Microscopic structural change in a liquid Fe-C alloy of ∼5GPa

Yuki Shibazaki, Yoshio Kono, Yingwei Fei

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The structure of a liquid Fe-3.5wt% C alloy is examined for up to 7.2GPa via multiangle energy-dispersive X-ray diffraction using a Paris-Edinburgh type large-volume press. X-ray diffraction data show clear changes in the pressure-dependent peak positions of structure factor and reduced pair distribution function at 5GPa. These results suggest that the liquid Fe-3.5wt% C alloys change structurally at approximately 5GPa. This finding serves as a microscopic explanation for the alloy's previously observed density change at the same pressure. The pressure dependencies of the nearest and second neighbor distances of the liquid Fe-3.5wt% C alloy are similar to those of liquid Fe which exhibits a structural change near the bcc-fcc-liquid triple point (5.2GPa and 1991K). Similarities between Fe-3.5wt% C and Fe suggest that a density change also occurs in liquid Fe and that this structural change extends to other Fe-light element alloys. Key Points The structure of liquid Fe-3.5wt% C is measured for up to 7.2GPa Liquid Fe-3.5wt% C changes structurally at 5GPa Structural changes in liquid Fe-C alloys are likely to induce density anomalies.

Original languageEnglish
Pages (from-to)5236-5242
Number of pages7
JournalGeophysical Research Letters
Volume42
Issue number13
DOIs
Publication statusPublished - 2015 Jul 16

Keywords

  • Fe-C alloy
  • high pressure
  • iron alloy
  • liquid structure
  • planetary core

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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