HR: 1340h
AN: MR43A-0975    [Abstracts]
TI: New Experimental Method for In Situ Determination of Material Textures at Simultaneous High-Pressure and –Temperature by Means of Radial Diffraction in the Diamond Anvil Cell.
AU: Liermann, H
EM: pliermann@hpcat.aps.anl.gov
AF: High-Pressure Collaboration Access Team, Geophysical Laboratory, Carnegie Institution of Washington, 9700 S. Cass Ave, Argonne, IL 60439, United States
AU: * Merkel, S
AF: LSPES - CNRS - Universite Lille 1, Batiment C6, Villeneuve d'Ascq, 59655, France
AU: Miyagi, L
AF: Earth and Planetary Science, University of California-Berkeley, 495 McCone Hall, Berkeley, CA 94720-4767, United States
AU: Wenk, H
AF: Earth and Planetary Science, University of California-Berkeley, 495 McCone Hall, Berkeley, CA 94720-4767, United States
AU: Shen, G
AF: High-Pressure Collaboration Access Team, Geophysical Laboratory, Carnegie Institution of Washington, 9700 S. Cass Ave, Argonne, IL 60439, United States
AU: Cynn, H
AF: High Pressure Physics Group, Lawrence Livermore National Lab, 7000 East Avenue, L- 041, Livermore, CA 94550, United States
AU: Evans, W J
AF: High Pressure Physics Group, Lawrence Livermore National Lab, 7000 East Avenue, L- 041, Livermore, CA 94550, United States
AB: Radial diffraction in the diamond anvil cell (DAC) has long been used to determine the stress state of materials under non-hydrostatic compression. This technique is also a major tool to investigate textures and infer deformation mechanisms in high pressure minerals. However, most of these experiments have been conducted at ambient temperatures and therefore the results of these measurements may be difficult to extrapolate to the deep Earth. Here, we present a new experimental design that was tested at HPCAT sector 16 BMD of the Advanced Photon Source. This method allows in situ measurement of stresses and textures in the DAC at simultaneously high- pressures and –temperatures. Details of this new technique that uses radial diffraction geometry are discussed, including the uses of amorphous boron gaskets, external heating using graphite heater, and membrane pressure control. Current coverage in pressure and temperature (~30 GPa and 1100 oC). The use of the method will be demonstrated with in situ texture measurements on the high-pressure phases of iron. In the experiment, we were able to observe strong textures in bcc-Fe, track the evolution of the texture with increasing temperature and during the bcc to fcc phase transition. Finally, we observed plastic deformation in the fcc phase between 5 and 15 GPa at 850 oC till the nucleation of hcp-Fe.
DE: 3902 Creep and deformation
DE: 3924 High-pressure behavior
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 8162 Rheology: mantle (8033)
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting