Bulletin of the American Physical Society
16th APS Topical Conference on Shock Compression of Condensed Matter
Volume 54, Number 8
Sunday–Friday, June 28–July 3 2009; Nashville, Tennessee
Session Q4: EOS-1: Equations of State |
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Chair: Jean-Paul Davis, Sandia National Laboratories Room: Hermitage D |
Wednesday, July 1, 2009 9:30AM - 9:45AM |
Q4.00001: Reloading Experiment for Aluminum at High Pressure Hou Rili, Peng Jianxiang, Zhang Jianhua, Tu Mingwu, Zhou Ping In the traditional AC method to measure material's dynamic strength, the combination flyer is easy to be delaminated due to shock waves produced in the projectile as a result of sudden application of the projectile driving pressure, which always result in the failure of reloading experiment. The maximum reshock experimental pressure for aluminum presented by Huang and Asay in 2005 is only 22GPa. A technique is described for reloading experiment, by which reloading experiments were performed for 2A12 aluminum alloy shocked to 67.6GPa. In our experiment, the oxygen-free copper and TC4 titanium alloy impactors were used with ultrapure LiF interferometer windows, 2A12 aluminum alloy samples were baked by PMMA buffers, and VISAR was used to measure interface particle velocity. Using an approximate double-step-sample method (two shots with different sample thickness at the same impact velocity), the Lagrange longitudinal velocities along reloading path from initial shock state were obtained, and coupled with unloading experimental data, the bulk velocities were determined, as well as the dynamic yield strength of 2A12 aluminum alloy. [Preview Abstract] |
Wednesday, July 1, 2009 9:45AM - 10:00AM |
Q4.00002: ABSTRACT WITHDRAWN |
Wednesday, July 1, 2009 10:00AM - 10:15AM |
Q4.00003: Multi--Phase Equations of State for Copper, Silver and Gold I.V. Lomonosov Results of theoretical calculations and experimental measurements of the equation of state (EOS)are discussed and applied to Cu, Ag and Au. A multi-phase EOS model is presented, accounting for solid, liquid, gas, and plasma states, as well as two--phase regions of melting and evaporation. The thermodynamic properties and phase diagrams are calculated with the use of this model. Theoretical calculations of thermodynamic properties of the solid, liquid, and plasma phases, and of the critical point, are compared with results of static and dynamic experiments. The analysis deals with thermodynamic properties of solid metal at T = 0 and 298 K from theories, static compression experiments in diamond anvil cells, and the information obtained in isentropic--compression and shock--wave experiments. Thermodynamic data in the liquid state, resulting from traditional thermophysical measurements, ``exploding wire'' experiments, and evaluations of the critical point are presented. Numerous shock--wave experiments have been done to measure shock adiabats of crystal and porous samples, release isentropes, and sound speed in shocked metal. These data are analyzed in a self--consistent manner together with all other available data at high pressure. The present EOS describes with high accuracy and reliability the complete set of available information. [Preview Abstract] |
Wednesday, July 1, 2009 10:15AM - 10:30AM |
Q4.00004: EOS and Spall Behavior of S200F Beryllium C.D. Adams, W.W. Anderson, G.T. Gray III, W.R. Blumenthal, C.T. Owens, F.J. Freibert, J.M. Montoya, P.J. Contreras This abstract is not available. [Preview Abstract] |
Wednesday, July 1, 2009 10:30AM - 11:00AM |
Q4.00005: Shock Waves and High-Energy-Density States of Matter in the GSI FAIR Team Project Invited Speaker: Knowledge of basic physical properties of matter under extreme conditions of high energy density, such as equation-of-state, static and dynamic electrical conductivity and opacity is of fundamental importance for various branches of basic and applied physics. Intense beams of energetic heavy ions provide a unique capability for heating macroscopic volumes of matter fairly uniformly and generating by this way high-density and highentropy states. This new approach permits to explore fascinating areas of the phase diagram that are difficult to access by other means. In this report we discuss various physics and technical issues of the high-energy-density physics research with intense heavy ions beams that is being performed at GSI, as well as that is to be carried out at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. [Preview Abstract] |
Wednesday, July 1, 2009 11:00AM - 11:15AM |
Q4.00006: Equation of State for Cerium at High Dynamic Pressures Konstantin V. Khishchenko Equations of state for matter over a wide range of pressures and temperatures are required for hydrodynamic simulations of processes in shock-compressed media. In this work, a new semiempirical equation of state for cerium is proposed with taking into account the polymorphic phase transformations, melting, evaporation, and ionization. Results of calculations of thermodynamic parameters of this metal in different phase states are compared with available experimental data at high dynamic pressures. [Preview Abstract] |
Wednesday, July 1, 2009 11:15AM - 11:30AM |
Q4.00007: First--Principles Thermoelasticity of Beryllium Philippe Legrand, Gregory Robert For a few years, we have been working to propose fully ab initio based models to the response of Beryllium to dynamic loading. Ab initio quantum mechanics, based on pseudopotentials, was used including Quantum Molecular Dynamics and phonon calculations. We have already constructed a thermodynamically complete and rigorous equation of state for Beryllium in the hexagonal and body-centred structures, obtained the melting curve and predicted elastic constants as a function of compression. The dependence of the elastic constants and shear modulus function of temperature was also taken into account under the hypothesis that the evolution of the Poisson ratio is independent of the temperature. To rise this hypothesis in our full ab initio scheme, we propose to proceed as follow: the crystal free energy is calculated by adding a static contribution which is accessible to standard DFT calculations to a dynamical contribution which is approximated by the free energy of a system of harmonic oscillators corresponding to the crystal vibrational modes (phonons) calculated within density-functional perturbation theory (DFPT). Then, the second derivatives of the free energy with respect to deformation give the full ab initio elastic constants dependence on temperature. [Preview Abstract] |
Wednesday, July 1, 2009 11:30AM - 11:45AM |
Q4.00008: Equation of State Measurements at Low Pressure in Tin Using of 800 MeV Proton Radiography Cynthia Schwartz, Gary Hogan, Nicholas King, Kris Kwiatkowski, Fesseha Mariam, Mark Marr-Lyon, Wendy McNeil, Frank Merrill, Chris Morris, Paul Rightley, Alexander Saunders A 2cm long 8 mm diameter cylindrical tin target has been shocked to a pressure in the region of the $\beta \diamondsuit \gamma $ phase change using a small, low density PETN charge mounted on the opposite side of a stainless steel diaphragm. The density jump and shock velocity were measured radiographically as the shock wave moved though the sample and the pressure dropped, using the proton radiography facility at LANL. This provided a quasi-continuous record of the equations of state along the Hugoniot for the P1 wave from a shock velocity of 3.25 km/sec down to near the sound speed. Edge release effects were removed from the data using tomographic techniques. The data show evidence for a phase transition that extends over a broad pressure range. The data and analysis will be presented. [Preview Abstract] |
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