Bulletin of the American Physical Society
15th APS Topical Conference on Shock Compression of Condensed Matter
Volume 52, Number 8
Sunday–Friday, June 24–29, 2007; Kohala Coast, Hawaii
Session P5: Equation of State IV |
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Chair: Choong-Shik Yoo, Lawrence Livermore National Laboratory Room: Fairmont Orchid Hotel Plaza III |
Thursday, June 28, 2007 10:30AM - 10:45AM |
P5.00001: Systematics of Compression of Hard Materials W. J. Nellis, T. Petach Hard materials are those for which the the Rayleigh line is close to Hugoniot, which means thermal pressures are small, which means Hugoniot, isentrope, and isotherm of a given material are nearly coincident up to 100 GPa pressures. Hard materials are used, for example, as anvils in reverberating shock experiments to look at quasi-isentropically compressed, highly-condensed low-Z fluids. For this reason, the shock impedances, optical transparencies, and electrical conductivities of these materials are of interest above 50 GPa. In this paper measured Hugoniots and isotherms of materials such as diamond, sapphire, titanium dioxide, GGG, etc will be used to derive systematic equation-of-state behavior for these materials. Major conclusions and future experiments will be discussed. [Preview Abstract] |
Thursday, June 28, 2007 10:45AM - 11:00AM |
P5.00002: Equation of State for Ti-Beta-21S Kevin Honnell, Nenad Velisavljevic, Chris Adams, Paulo Rigg, Gary Chesnut, Robert Aikin, Jr., Jonathan Boettger A new, tabular, SESAME equation of state is presented for Ti-Beta-21S (TIMETAL 21S{\textregistered}), a high-strength, high-temperature, beta-stabilized alloy of Ti, Mo, Nb, and Al. The new equation of state combines an empirical, Vinet description of the cold curve with the Johnson ionic model and the Thomas-Fermi-Dirac model for the thermal electronic contributions. Both the HCP and BCC phases are accounted for via the cold curve. Predictions for the room-temperature isotherm, principal Hugoniot, and thermal expansion are compared to new experimental results. [Preview Abstract] |
Thursday, June 28, 2007 11:00AM - 11:15AM |
P5.00003: An Equation of State study of a Boron Nitride rubber composite using a Single Stage Gas Gun Peter Taylor, Peter Keightley The equation of state of a Boron Nitride powder / Neoprene / Polythene composite has been determined experimentally up to 5GPa using a single stage Helium gas gun. The newly commissioned gun operates using a fast acting gas valve breech, and is capable of launching a 65mm diameter flyer at up to 1km/s. A series of 1D plate impact experiments has been employed using a shock reverberation or ring-up technique in which the sample is sandwiched between layers of a higher shock impedence material. Manganin stress gauges are used to measure the stress levels and shock arrival times as the shocks reverberate within the sample layer. The Hugoniot has been determined from the measured stress and shock velocity at several impact velocities for the first shock. Subsequent reflected shocks within the sample have been measured and used to determine off Hugoniot states and hence Gruniesen Gamma in order to derive the equation of state. [Preview Abstract] |
Thursday, June 28, 2007 11:15AM - 11:30AM |
P5.00004: On the applicability of analytical models to predict Hugoniot of nano-sized powder compacts. Chengda Dai, Daniel Eakins, Naresh Thadhani Hugoniot of nano-sized powder pre-pressed to varied porosities is crucial for design of shock compaction experiments to fabricate bulk consolidated nanostructured compacts and for validation of the equation of state over a wide range of density and temperature. The McQueen and Wu-Jing models are representatives of isochoric and isobaric approaches to predicting porous Hugoniot. Both models, however, neglect the difference in internal energy between the powder compact and solid. Hence, it is uncertain if the models can still be applied to predict the Hugoniot of nanoparticle compact due to the high specific surface energy of nanoparticles relevant to specific internal energy. In the present work, we review the two models, focusing on their main assumptions and resultant restrictions, and show the increasing deviation of the predicted Hugoniot with increasing porosity from the available experimental data. We have also used piezoelectric stress gages to measure the Hugoniot of 25nm-Fe powder pre-pressed to 35{\%} and 45{\%} solid density. Experimental data show that the measured Hugoniot data are not fully consistent with the predicted results. Both models may be improved to predict Hugoniot of nanoparticle compacts by considering the characteristic properties of nano-sized particles. [Preview Abstract] |
Thursday, June 28, 2007 11:30AM - 11:45AM |
P5.00005: Shock compression and equation of state of C$_{60}$ fullerite Vladimir Milyavskiy, Konstantin Khishchenko, Alexander Utkin, Vladislav Yakushev, Andrey Zhuk, Vladimir Fortov Recently, we have experimentally studied shock compressibility of C$_{60}$ fullerite and sound velocity in shock-compressed fullerite [1]. The Hugoniot of C$_{60}$ fullerite had a set of peculiarities. Appearance of a rather hard carbon phase was detected at shock pressure $\sim$ 9 GPa. We assume that it is a 2D-polymerized C$_{60}$ phase. With increase of shock pressure, destruction of this phase and formation of a graphite-like carbon occurs. With further increase of shock pressure, the graphite- like carbon transforms to a diamond-like phase. If shock pressure is higher than $\sim$ 33 GPa, shock compressibility of C$_{60}$ fullerite is determined by the thermodynamic properties of the diamond-like phase. The results of the shock-wave measurements were used for the description of thermodynamic properties of C$_{60}$ fullerite and products of its transformations in a wide range of pressures and temperatures. A semiempirical equation of state for the simple cubic phase of C$_{60}$ fullerite is proposed. The EOS we have developed for fullerite C$_{60}$ provides a consistent representation of the available experimental data. The work was supported by RFBR. [1] Milyavskiy V.V., Utkin A.V., Zhuk A.Z., Yakushev V.V. and Fortov V.E. Diamond and Rel. Mat. 14 (2005) 1920. [Preview Abstract] |
Thursday, June 28, 2007 11:45AM - 12:00PM |
P5.00006: Dynamic Loading of Teflon at 200$^{\circ}$C Paul A. Urtiew, Jerry W. Forbes, Craig M. Tarver, Kevin S. Vandersall, Frank Garcia Dynamic loading experiments were performed on inert Teflon (Polytetrafluoroethylene) samples, initially heated to the temperature of 200$^{\circ}$C, to test its behavior under these conditions for their use in other heated experiments. Tests were performed in the 100 mm diameter bore propellant driven gas gun with piezo-resistive manganin pressure gauges imbedded into the samples to measure loading pressures. Experimental data provided new information on the shock velocity -- particle velocity relationship for the heated material and showed no effect of temperature on the non-conducting property of the material being used as an electrical insulator. This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. [Preview Abstract] |
Thursday, June 28, 2007 12:00PM - 12:15PM |
P5.00007: Shock Hugoniot Behavior for Particle Reinforced Polymer Composites Louis Ferranti, Jr., Naresh Thadhani, Jennifer Jordan, Richard Dick The shock Hugoniot for polymers exhibits a non-linear $U_{S}-U_{P}$ relationship at relatively low pressures, showing a concave curvature with an initially rapid shock velocity. In contrast, the shock Hugoniot for a particle reinforced polymer composite displays a convex curvature with initially rapid particle velocity. Transformation to pressure-volume space shows an initial expansion that is not related to a low-pressure phase change or reaction, but rather the decohesion of solid particles from the polymer matrix. We will report on equation of state experiments conducted for epoxy-cast Al+Fe$_{2}$O$_{3}$ composites showing deviation from ideal Hugoniot behavior as a result of damage evolving at a critical impact stress. Two compositions prepared with significantly different volume fractions of polymer binder phase show damage occurring at approximately the same critical impact stress. The Burch-Murnaghan EOS is used to show the introduction of damage. Further validation of this effect is obtained from a constitutive model for tensile damage and distention (TDD) behavior available in the shock physics code, CTH. [Preview Abstract] |
Thursday, June 28, 2007 12:15PM - 12:30PM |
P5.00008: Measurements of the release of alpha quartz: a new standard for impedance-match experiments Thomas Boehly, Joshua Miller, Jon Eggert, Peter Celliers, Damien Hicks, Stephanie Brygoo, David Meyerhofer, Gilbert Collins Previous laser-driven-shock measurements of the kinematic$^{1}$ and thermal$^{2}$ properties of alpha quartz at 200-1500 GPa enabled the use of quartz as a reshock `anvil'$^{3}$, a pressure witness$^{1}$, and a temperature reference$^{4}$. We present measurements of the release of alpha quartz into SiO2 aerogel whose EOS had been calibrated by direct measurments$^{5}$. These results establish alpha quartz as an impedance-match standard which, because of its transparency, enables accurate measurements of the velocity (pressure) profile in the pusher. [1] Hicks, D. G., \textit{et al.} Phys. Plasmas 12, 082702 (2005). [2] Hicks, D. G., \textit{et al.} Phys Rev Lett 97, 025502 (2006) [3] Boehly, T. R\textit{ et al}. Phys. Plasmas 11(9): L49-L52 (2004). [4] Brygoo, S \textit{et al.} Ph.D. thesis, publicaton in prep. [5] Knudson, M. \textit{et al.} JAP 97, 073514 (2005) Supported by the USDOE Office of Inertial Confinement Fusion under Coop. Agreement No. DE-FC03-92SF19460, the U. of Rochester, and the NYSEDA. This support does not constitute an endorsement by DOE of the views expressed in this article. [Preview Abstract] |
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