The Study of High Pressure and Bulk Modulus of Metals by Equations of State

2016 ◽  
Vol 5 (3) ◽  
pp. 397-400
Author(s):  
R. S. Singh ◽  
Deepti Sahrawat
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Equations Of State

Elastic Properties of Calcium Oxide Perovskites

2002 ◽  
Vol 718 ◽  
Author(s):  
Nancy L. Ross ◽  
Ross J. Angel ◽  
Jennifer Kung ◽  
Tracey D. Chaplin
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Calcium Oxide ◽  
Specific Volume ◽  
Equations Of State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Threefold Increase ◽  
Volume Relationship ◽  
Brownmillerite Structure

AbstractThe equations of state and axial moduli of the CaBO3 perovskites (B=Zr,Sn,Ti,Ge) and CaFeO2.5 with the brownmillerite structure have been determined using high-pressure, singlecrystal X-ray diffraction. The bulk modulus-specific volume relationship for the Ca-perovskites is nonlinear, with CaSnO3 and CaZrO3 displaying anomalous stiffening (higher bulk moduli) than previously reported and predicted [1,2]. The axial moduli of the a- and c-axes decrease steadily by ∼30% from the least-distorted of the Pbnm perovskites, CaGeO3, to the most distorted, CaZrO3, while the b-axis shows little change. The net result is a threefold increase in the anisotropy of the axial moduli of CaSnO3 and CaZrO3 (∼21%) relative to CaGeO3 and CaTiO3 (∼4-8%). The bulk modulus of CaFeO2.5 falls significantly below the trend for the stoichiometric perovskites. The introduction of 1/6 vacancies on the oxygen positions softens the perovskite structure by 25%.

scholarly journals Theoretical Study of Mechanical, Elastic and Phonon Frequency Spectrum Properties for GaAs at High Pressure

2019 ◽  
pp. 371-378
Author(s):  
Raed H. AL-Saqa ◽  
Siham J. AL-Taie
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Frequency Spectrum ◽  
Lattice Constant ◽  
Room Temperature ◽  
Theoretical Study ◽  
Phonon Frequency ◽  
Equations Of State

The calculations for variations of bulk modulus (B), compression volume (Vp Vo ); lattice constant and phonon frequency spectrum (pfs) under high pressure up to 17 GPa at room temperature has been carried out. Three equations of state (EOSs) including (Birch- Murnaghan, Vinet and modified Lennard-Jouns) are used in the calculations. The variations of these properties under such high pressure for GaAs are obtained and we got suitable EOS for it.

Seismic parameter φ: Computation at very high pressure from laboratory data

1966 ◽  
Vol 56 (3) ◽  
pp. 725-731
Author(s):  
Orson L. Anderson
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Ultrasonic Velocity ◽  
Pressure Range ◽  
High Pressures ◽  
Equations Of State ◽  
Laboratory Data ◽  
Second Derivative ◽  
Velocity Measurements ◽  
Very High

abstract By using the accuracy inherent in ultrasonic velocity measurements taken at pressures less than 10 kb, the seismic parameter φ=vp2−(43)vS2 can be computed at very high pressures. The equation used requires the assumption that the second derivative with respect to pressure of the bulk modulus be negligible at all pressures considered. This assumption is checked by computing the compression (V/V0) in the pressure range by equations of state using the assumption, and comparing the resulting values with measured compression. Illustrations are given for MgO and Al2O3.

The effect of Al/Si disorder on the bulk moduli of plagioclase feldspars

2010 ◽  
Vol 74 (6) ◽  
pp. 943-950 ◽  
Author(s):  
L. M. Sochalski-Kolbus ◽  
R. J. Angel ◽  
F. Nestola
Keyword(s):  
Bulk Modulus ◽  
Single Crystal ◽  
Equations Of State ◽  
X Ray Diffraction ◽  
Volume Increase ◽  
X Ray ◽  
Density Decrease ◽  
The Relationship

AbstractThe volumes of a disordered An20 (Qod = 0.15), a disordered An78 (Qod = 0.55) and an ordered An78 (Qod = 0.81) were determined up to 9.569(10) GPa, 8.693(5) GPa and 9.765(10) GPa, respectively, using single-crystal X-ray diffraction. The volume variations with pressure for these samples are described with 4th-order Birch Murnaghan equations of state with V0 = 669.88(7) Å3, K0 = 59.7(7) GPa. K′ = 5.7(5), K″ = −0.8(2) GPa−1 for disordered An20, V0 = 1340.48(10) Å3, K0 = 77.6(5) GPa, K0′ = 4.0(3), K″ = -0.59(9) GPa−1 for disordered An78 and V0 = 1339.62(6) A3, K0 = 77.4(6) GPa, K′ = 4.2(4), and K″ = −0.7(1) GPa−1 for ordered An78. Along with data from previous studies (An0 ordered, An0 disordered and An2o ordered), the volumes for the disordered samples were found to be up to ∼0.3% larger than the ordered samples of the same composition. The disordered samples are softer than the ordered samples of the same composition by 4(1)% for An0, 2.5(9)% for An20 and essentially zero for An78. The relationship between volume increase, density decrease, and decreasing bulk modulus with increasing disorder is in accordance with Birch's Law.

High-pressure phase transitions and the equations of state of BaS and BaO

1986 ◽  
Vol 33 (6) ◽  
pp. 4221-4226 ◽  
Author(s):  
Samuel T. Weir ◽  
Yogesh K. Vohra ◽  
Arthur L. Ruoff
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Equations Of State ◽  
High Pressure Phase ◽  
Pressure Phase

Equation of state for the detonation products of energetic materials

2021 ◽  
Vol 11 (8) ◽  
pp. 1269-1287
Author(s):  
Xiangyu Huo ◽  
Li Zhang ◽  
Mingli Yang
Keyword(s):  
Artificial Intelligence ◽  
High Pressure ◽  
Computer Simulations ◽  
Energetic Materials ◽  
Equations Of State ◽  
Experiment Study ◽  
Detonation Products ◽  
Main Approach ◽  
Practical Applications ◽  
Integrated Theory

Energetic materials (EMs) are one of the necessities in many military and civilian applications. Measuring the thermodynamic behaviors of detonation products of EMs at high temperature and high pressure, their equations of state (EOSs) not only serve as a basis in the design of novel materials, but also provide valuable information for their practical applications. The EOS study has a long history, but keeps moving all the time. Various EMs have been developed, the EOS of detonation products provides abundant information in the thermochemistry, hydromechanics and detonation physics, which in turn feedbacks the development of novel EMs and their EOSs. With the development of experimental techniques and computer simulations, many EOSs have been proposed for various explosives in recent years. While experiments keep their fundamental roles, integrated theory-experiment study has become the main approach to the EOS establishment for novel EMs. Moreover, computer simulations based on interatomic and/or intermolecular interaction will have great potential in the future when big data and artificial intelligence are introduced into the field.

Deformation of polyiodides in Cs2I8 crystals at high pressure

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Tomasz Poreba ◽  
Gaston Garbarino ◽  
Davide Comboni ◽  
Mohamed Mezouar
Keyword(s):  
High Pressure ◽  
Electron Transfer ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
Supramolecular Architecture ◽  
Ambient Conditions ◽  
Electron Transfer Mechanism ◽  
Covalently Bonded ◽  
Potential Sources ◽  
High Bulk

Dicaesium octaiodide is composed of layers of zigzag polyiodide units (I8 2−) intercalated with caesium cations. Each I8 2− unit is built of two triiodides bridged with one diiodine molecules. This system was subjected to compression up to 5.9 GPa under hydrostatic conditions. Pressure alters the supramolecular architecture around I8 2−, leading to bending of the triiodide units away from their energetically preferred geometry (D ∞h). Short I2...I3 − contacts compress significantly, reaching lengths typical for the covalently bonded polyiodides. Unlike in reported structures at ambient conditions, pressure-induced catenation proceeds without symmetrization of the polyiodides, pointing to a different electron-transfer mechanism. The structure is shown to be half as compressible [B0 = 12.9 (4) GPa] than the similar CsI3 structure. The high bulk modulus is associated with higher I—I connectivity and a more compact cationic net, than in CsI3. The small discontinuity in the compressibility trend around 3 GPa suggests formation of more covalent I—I bonds. The potential sources of this discontinuity and its implication on the electronic properties of Cs2I8 are discussed.

High pressure studies on the packing forces and intermolecular interaction in polyphenyls

2003 ◽  
Vol 771 ◽  
Author(s):  
G. Heimel ◽  
P. Puschnig ◽  
M. Oehzelt ◽  
K. Hummer ◽  
B. Koppelhuber-Bitschnau ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Structural Changes ◽  
Equations Of State ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Pressure Derivative ◽  
Molecular Arrangement ◽  
High Pressure Studies ◽  
Phenyl Rings ◽  
Induced Changes

AbstractIn this work, we report on pressure induced structural changes in crystalline oligo(paraphenylenes) containing two to six phenyl rings. Revisiting the crystal structures at ambient conditions reveals details in the packing principle. A linear relationship between the density at ambient conditions and the number of phenyl rings is found. Energy dispersive X-ray diffraction has been performed in a systematic study on polycrystalline powders of biphenyl, paraterphenyl, p-quaterphenyl, p-quinquephenyl and p-sexiphenyl under hydrostatic pressure up to 60 kbar. Our investigations not only yield pressure dependent lattice parameters and hints towards pressure induced changes in the molecular arrangement, but also allow for an analysis of the equations of state of these substances as a function of oligomer length. We report the previously unknown bulk modulus of p-quaterphenyl, p-quinquephenyl, and p-sexiphenyl (B0 = 83 kbar, 93 kbar, and 100 kbar respectively) and its pressure derivative (B0' = 6.4, 7.5, and 5.6). A linear dependence of the bulk modulus on the inverse number of phenyl rings in the molecules is found.

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