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

Duffy, TS and Shen, Guoyin and Shu, Jinfu and Mao, HK and Hemley, RJ 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: 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)
Depositing User: Users 11 not found.
Date Deposited: 06 Jun 2008
Last Modified: 17 Aug 2015 10:26
URI: http://nal-ir.nal.res.in/id/eprint/4670

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