Browsing by Author "Rivers, ML"

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    High pressure single-crystal micro X-ray diffraction analysis with GSE_ADA/RSV software
    (Taylor & Francis Ltd., 2013-06-17) Dera, P; Zhuravlev, K; Prakapenka, V; Rivers, ML; Finkelstein, GJ; Grubor-Urosevic, O; Tschauner, O; Clarke, SM; Downs, RT
    GSE_ADA/RSV is a free software package for custom analysis of single-crystal micro X-ray diffraction (SCμXRD) data, developed with particular emphasis on data from samples enclosed in diamond anvil cells and subject to high pressure conditions. The package has been in extensive use at the high pressure beamlines of Advanced Photon Source (APS), Argonne National Laboratory and Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. The software is optimized for processing of wide-rotation images and includes a variety of peak intensity corrections and peak filtering features, which are custom-designed to make processing of high pressure SCμXRD easier and more reliable. © 2013, Taylor & Francis.
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    Rheology of ε-iron up to 19 GPa and 600 K in the D-DIA
    (American Geophysical Union, 2007-12-07) Nishiyama, N; Wang, YD; Rivers, ML; Sutton, SR; Cookson, DJ
    Stress-strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline ε-iron have been obtained at pressures of 17(±1) GPa, three different temperatures (600, 400, and 300 K), and various strain rates between 3.8 × 10−6 and 2.3 × 10−5 s−1 using the deformation-DIA coupled with monochromatic X-rays. Five independent stress-strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4% axial strain, sample stresses reach saturation and the sample exhibited steady-state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be ∼31 and ∼7, respectively. These results indicate that ε-iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power-law creep. The overall deformation behavior for ε-iron is consistent with that of zinc, suggesting that the deformation mechanism map of ε-iron resembles those of other hexagonal metals. © 2007, American Geophysical Union