3:00 PM - 3:15 PM
[SCG54-12] Rheology of hcp-iron
Keywords:hcp-iron, inner core, rheology
Uniaxial deformation experiments were carried out using a D111-type apparatus installed on a beamline NE7A at PF-AR, KEK and a deformation-DIA apparatus installed on a beamline BL04B1 at SPring-8. Using polycrystalline bcc-iron as a starting material, deformation experiments were carried out at pressure of 16.9-22.6 GPa, temperature of 423-873 K, and strain rate of 0.2–5.2×10–5 s–1. Stress and strain during deformation were determined based on two-dimensional X-ray diffraction and X-radiography, respectively, using monochromatized synchrotron X-ray with energy of 60 keV.
A preliminary analysis of the observed data suggests that power-law dislocation creep with stress exponent of ~5 is dominant at >700 K whereas power-law breakdown occurs at lower temperatures. Extrapolation of the data based on homologous temperature scaling suggests that viscosity of hcp-iron at the inner core conditions is ~1021 Pa s or higher.