Elasticity, shear strength, and equation of state of molybdenum and gold from x-ray diffraction under nonhydrostatic compression to 24 GPa

Duffy, Thomas S and Shen, Guoyin and Shu, Jinfu and Mao, Ho-Kwang and Hemley, Russell J and Singh, AK (1999) Elasticity, shear strength, and equation of state of molybdenum and gold from x-ray diffraction under nonhydrostatic compression to 24 GPa. Journal of Applied Physics, 86 (12). pp. 6729-6736.

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    Abstract

    Lattice strains were measured as a function of the angle @ between the diffracting plane normal and the stress axis of a diamond anvil cell in a layered sample of molybdenum and gold. The sample was compressed over the range 5-24 GPa and the lattice strains were measured using energy-dispersive x-ray diffraction. As @ is varied from 0quot; to 90x201D; , the mean lattice parameter of molybdenum increases by up to I .2% arid that of gold increase by up to 0.7%. A linear relationship between Q( hkl) , which is related to the dupe of the measured (I spacing versus 1-3 cos' @ relation.13; 3 T ( h k i ) , a function of the Miller indices of the diffracting plane, is observed for both material13; predicted by theory. The pressure dependence of the uniaxial stress r for gold from this and other recent studies is given by r=0.06+0.015P, where P is the pressure in GPa. The uniaxial stress in molybdenum can he described by r=0.46+0.13P. Using gold :IS an internal pressure standard, the equation of state of molybdenum depends strongly on $. The hulk modulus obtained from a Birch-Murnaghan fit varies from 210 to 148 GPa as varies from 0quot; 10 YOquot;. However, an equation of state in good agreement with shock and ultrasonic isotherms is obtained for @=54.7quot; where the13; deviatoric contribution to the lattice strain vanishes. Second-under elastic moduli for gold and molybdenum are obtained from the data. The results are generally consistent with an earlier x-ray study and with extrapolations of low-pressure ultrasonic data. The pressure dependence of the shear modulus C,, is smaller for the x-ray data than predicted by extrapolation of ultrasonic data.

    Item Type: Journal Article
    Additional Information: Copyright for this article belongs to American Institute of Physics
    Uncontrolled Keywords: GSECARS;Elasticity;Shear strength;X-ray diffraction; Nonhydrostatic compression
    Subjects: CHEMISTRY AND MATERIALS > Composite Materials
    CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
    Division/Department: Other, Other, Other, Other, Other, Materials Science Division
    Depositing User: Ms. Alphones Mary
    Date Deposited: 06 Jun 2008
    Last Modified: 17 Jun 2010 10:43
    URI: http://nal-ir.nal.res.in/id/eprint/4670

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