11:42 AM - 11:45 AM
[SIT06-P06] Sound velocity measurements of solid iron under high pressure and high temperature using an ultrasonic method
3-min talk in an oral session
Simultaneous ultrasonic measurements, and X-ray radiography and diffraction experiments were carried out at BL04B1 beamline, SPring-8 in Japan. High-pressure and high-temperature were generated using a 1500-ton Kawai type multi-anvil apparatus installed at BL04B1 beamline. The experimental conditions were up to 7 GPa and 800 K (stability field of bcc-Fe). The Fe powder or rod was used as the sample. Ultrasonic VP and VS measurements were performed using the pulse reflection method. P- and S-wave signals with a frequency of 57 MHz and 30 MHz, respectively, were generated and received by a 10 degree Y-cut LiNbO3 transducer. The sample was first compressed to the target pressure and heated up to the maximum temperature in each press load in order to reduce the deviatoric stress. Then, we got the ultrasonic data, X-ray radiography image, and X-ray diffractions from the sample and the pressure marker (MgO + hBN) at each about 150-200 K temperature step on decreasing temperature.
Our high-pressure VP and VS data are good agreement with the previous ambient-pressure results measured using the same ultrasonic method [Dever, 1972]. In contrast, our VP data are slightly smaller than the results obtained by high-energy resolution inelastic X-ray scattering (HERIX) technique [Liu et al., 2014]. The values of both VP and VS at high temperature are lower than the linear relationship of a velocity-density, i.e., Birch's law, at room temperature, which is the same trend as the previous HERIX result [Liu et al., 2014].