Strength of rhenium from x-ray diffraction experiments under nonhydrostatic compression to 250 GPa

Singh, AK and Hu, J and Shu, J and Mao, H-k and Hemley, RJ (2012) Strength of rhenium from x-ray diffraction experiments under nonhydrostatic compression to 250 GPa. In: 23rd International Conference on High Pressure Science and Technology (AIRAPT-23): Journal of Physics: Conference Series 377 (2012) 012008, 25–30 September 2011, BARC, Mumbai.

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    Abstract

    Polycrystalline rhenium in the form of a powder contained in a two-stage gasket was compressed in a diamond anvil cell. No pressure medium was used to ensure that maximum nonhydrostatic stresses that rhenium can support were produced. The pressure was increased in steps to a maximum of 250 GPa and the diffraction pattern recorded at each pressure using energy dispersive technique. The differential stress t, a measure of the compressive strength, was determined at any given pressure from the offset between the measured unit cell volume and volume computed from the pressure-volume relation under hydrostatic pressure. The data suggest that t is 2.5 GPa at a pressure of 5 GPa and increases linearly to 26 GPa at 250 GPa. The present data agree well with those obtained from the radial diffraction data to 37 GPa in an earlier study but differ significantly from the results of another study. Though comparable with the theoretical strength of ideal solids, the observed strengths are extremely large for a polycrystalline aggregate of a solid. The pure pressure effect on the strength described by the shear modulus scaling is inadequate to account for such a large increase of strength with pressure . It is suggested that the major contribution to strength comes from the strain hardening of rhenium that arises due to plastic deformat ion of the sample during nonhydrostatic compression in a diamond anvil cell.

    Item Type: Conference or Workshop Item (Paper)
    Uncontrolled Keywords: Rhenium;X-ray diffraction;Nonhydrostatic compression
    Subjects: CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
    Division/Department: Materials Science Division, Other, Other, Other, Other
    Depositing User: Smt Bhagya Rekha KA
    Date Deposited: 23 Aug 2012 10:57
    Last Modified: 23 Aug 2012 10:57
    URI: http://nal-ir.nal.res.in/id/eprint/10838

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