Yield strength at high pressure and temperature

Weidner, Donald J.; Wang, Yanbin; Vaughan, Michael T.

doi:10.1029/93gl03549

Cited by 160 publications

(77 citation statements)

References 17 publications

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“…), but at multimegabar pressures even helium could not provide hydrostatic conditions, and we did not use any pressure medium above 100 GPa. However, homogeneous heating above 1,000 K drastically reduces stresses (4,32,33) (Fig. 2b).…”

Section: Resultsmentioning

confidence: 99%

Aggregate sound velocities and acoustic Grüneisen parameter of iron up to 300 GPa and 1,200 K

Dubrovinsky

Bihan

2001

Proc. Natl. Acad. Sci. U.S.A.

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Successful interpretation of available geophysical data requires experimental and theoretical information on the elasticity of solids under physical conditions of Earth's interior. Because iron is considered as major component in Earth's core, elastic properties of iron at high pressures and temperatures are very important for modeling its composition and dynamics. We use in situ x-ray diffraction data on -iron at static pressures up to 300 GPa and temperatures to 1,200 K to determine the Debye-Waller temperature factors and calculate aggregate sound velocities and Grü neisen parameter of -iron by using an approach that is based on Rietveld refinement at high pressures and temperatures.T he data on static compression of iron at ambient and elevated temperatures (1-4) provides important information on compressibility at the conditions present in Earth's deep interior. However, information on shear modulus, which is crucial for calculating sound velocities, is very limited. Mao et al. (5) published results of a study of elasticity of iron to a pressure of 220 GPa based on a novel method of determination of elastic moduli with diamond anvil cells (DAC) (6). This method utilizes the fact that in opposite anvil devices (like DAC) compression is not hydrostatic. As a result, positions of the reflections on the powder diffraction patterns depend not only on bulk modulus of the compressed material, but also on all of the elastic moduli and a value of deviatoric stress. The method cannot be used at high temperatures because deviatoric stress in DAC practically vanishes above Ϸ800 K (4). The mean sound velocities of hcp iron were extracted from phonon density measurements at pressures up to 153 GPa and ambient temperature (7,8). Raman spectroscopy (9) of -Fe at pressures up to 150 GPa gave additional input to elastic properties of iron at high pressures. However, so far there are no experimental information on sound velocities of iron at pressure range of 300 GPa and high temperaturesconditions that are relevant to Earth's inner core.The vibrations of individual atoms, as applied to intensities of x-ray diffraction peaks, control the Debye-Waller temperature factor B. This includes all wavelengths of phonons. As a result, the information on temperature factors has been used over years to determine Debye temperatures and Gruneisen parameters of different materials (10-15). The Debye temperature depends on aggregate elastic properties of a crystal-the adiabatic bulk modulus K S and shear modulus G (16). Moreover, it was demonstrated by Anderson (16) that the Debye temperature is primarily dependent on the shear modulus, and this opens the way, as we are going to show in the present study, to extract aggregate shear and compressional sound velocities from data on temperature factors. Following Grimvall's (12) consideration and using dispersion relation (10, 11)where is the circular frequency, V sound is the sound velocities, q is the wave number of a lattice mode, and q D is the Debye cut-off wave number. We found for the ...

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Section: Resultsmentioning

confidence: 99%

Aggregate sound velocities and acoustic Grüneisen parameter of iron up to 300 GPa and 1,200 K

Dubrovinsky

Bihan

2001

Proc. Natl. Acad. Sci. U.S.A.

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“…Information on deviatoric stress as a function of time allows us to locate the yield point of the material and thus obtain yield strength (e.g., [573]). The yield strength of some mantle minerals at HP-HT has been determined [573][574][575][576][577].…”

Section: Strengthmentioning

confidence: 99%

High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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“…The diffraction-line broadening has been used to determine the maximum stress in the stress distribution in the crystallites. [2][3][4][5][6][7][8][9][10][11][12] The maximum stress p max (ffi eY, where e and Y are the micro-strain and the aggregate Young's modulus, respectively) is often termed the micro-differential stress (micro-DS) and is taken as the measure of compressive strength of the polycrystalline sample material. Some studies used p max (e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

Strength of polycrystalline niobium from high-pressure x-ray diffraction data: A comparison of results from line-width and line-shift analyses

Singh

Liermann

2015

Journal of Applied Physics

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High purity polycrystalline niobium was compressed in a diamond anvil cell (DAC) without any pressure transmitting medium and the pressure was increased in steps of ∼5 GPa to the highest pressure of ∼40 GPa. The diffraction pattern was recorded after each pressure increment using angle-dispersive mode with the conventional diffraction geometry, wherein the primary x-ray beam is parallel to the load axis of the DAC. The strength of niobium as function of pressure was determined using the line-width and line-shift analyses. Both eY and 2eY, where Y is the aggregate Young's modulus and e is the strain determined from the line-width analysis, have been used as the measure of strength in earlier studies. In this study, it is eY that agrees with the strength determined from the line-shift analysis of the radial diffraction data as well as the data from the conventional diffraction geometry. These results have been discussed and compared with a similar observation made earlier on strength of diamond. This study highlights the ambiguity that presently exists in choosing eY or 2eY as a measure of strength while attempting to estimate the strength from the diffraction line width analysis.

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Yield strength at high pressure and temperature

Cited by 160 publications

References 17 publications

Aggregate sound velocities and acoustic Grüneisen parameter of iron up to 300 GPa and 1,200 K

Aggregate sound velocities and acoustic Grüneisen parameter of iron up to 300 GPa and 1,200 K

High-pressure studies with x-rays using diamond anvil cells

Strength of polycrystalline niobium from high-pressure x-ray diffraction data: A comparison of results from line-width and line-shift analyses

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