Sound velocity measurements of hcp Fe-Si alloy at high pressure and high temperature by inelastic X-ray scattering

摘要

The sound velocity of hcp Fe0.89Si0.11 (Fe-6wt% Si) alloy was measured at pressures from 45 to 84 GPa and temperatures of 300 and 1800 K using inelastic X-ray scattering (IXS) from laser-heated samples in diamond-anvil cells (DACs). The compressional velocity (v(P)) and density (rho) of the Fe-Si alloy are observed to follow a linear relationship at a given temperature. For hcp Fe0.89Si0.11 alloy we found v(P) = 1.030 (+/- 0.008) x rho - 1.45 (+/- 0.08) + [3.8 x 10(-5)(T - 300) x(rho - 15.37)], including non-negligible temperature dependence. The present results of sound velocity and density of hcp Fe0.89Si0.11 alloy indicates that 3 similar to 6 wt% of silicon in the inner core with additional amount of Ni can explain the compressional velocity (vP) and density (r) of the "preliminary Earth reference model" (PREM), assuming a temperature of 5500 K and that silicon is the only light element in the inner core