Sound velocities in the Fe-Si-C alloys at extreme conditions: Si and C in the core

The experiment aims to investigate the elastic and thermodynamic properties of Fe-Si-C alloy at pressures above 200 GPa and temperatures of thousands of degrees by means of the Nuclear Inelastic Scattering (NIS) technique and powder X-ray diffraction. NIS is a powerful tool for the study of lattice dynamics that provides a full thermodynamic sample characterization. The measured phonon density of states provides the Debye phonon average velocity (VD), which together with density and bulk modulus, determined by complementary X-ray diffraction measurements, are the necessary parameters for calculating the compressional velocity (VP) and shear velocity (VS) of the material. Our measurements will allow refining the amount of Si and C required to explain the observed seismic profile of the Earth’s core.