HR: 0800h
AN: MR31B-0368    [Abstracts]
TI: Effects of Si on the crystal structure and elastic property of Fe at Earth's inner core pressures
AU: Fujibuchi, M
EM: takut@sci.ehime-u.ac.jp
AF: Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan
AU: * Tsuchiya, T
EM: takut@sci.ehime-u.ac.jp
AF: Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama, 790-8577, Japan
AB: Earth's inner core is generally thought to consist of Fe-Ni alloy. Some amount of light elements are also expected to be dissolved. Recent high-pressure experiments and theoretical simulations have suggested Si to be a highly possible candidate of impurity elements in the inner core. In this study, we investigated the effects of Si on the crystal structure and elastic property of iron at the Earth's inner core pressures by first-principle calculations. Calculations show that Si changes the elasticity of the hcp and fcc phase of iron, in particular shear components, while it marginally affects bcc phase. As a result, V_S of hcp iron unexpectedly decreases even by incorporating light Si. Velocity-density relations of Fe-rich alloys are found very different from those anticipated from B2-type FeSi. Research supported by the Ehime Univ Project Fund.
DE: 1015 Composition of the core
DE: 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124)
DE: 3909 Elasticity and anelasticity
DE: 3924 High-pressure behavior
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting