Multi-phase equation of state for aluminum

Ломоносов, И. В.

doi:10.1017/s0263034607000687

Cited by 154 publications

(90 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 6061 alloy is less dense than aluminum 1100 and demonstrates a slightly stronger shock response 5 . While previous EOS for aluminum have been constructed [6][7][8] , none provide the high pressure solid phases, or have had access to the broad range of high accuracy simulations we have performed to constrain particularly the liquid state. However, several recent EOS have been constructed for different materials which are both multiphase and inclusive of the warm dense matter regime, and have also highly relied on simulation data [9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Multiphase aluminum equations of state via density functional theory

2016

View full text Add to dashboard Cite

We have performed density functional theory (DFT) based calculations for aluminum in extreme conditions of both pressure and temperature, up to 5 times compressed ambient density and over 1 000 000 K in temperature. In order to cover such a domain, DFT methods including phonon calculations, quantum molecular dynamics, and orbital-free DFT are employed. The results are then used to construct a SESAME equation of state for the aluminum 1100 alloy, encompassing the fcc, hcp and bcc solid phases as well as the liquid regime. We provide extensive comparison with experiment and based on this we also provide a slightly modified equation of state for the aluminum 6061 alloy.

show abstract

Section: Introductionmentioning

confidence: 99%

Multiphase aluminum equations of state via density functional theory

2016

View full text Add to dashboard Cite

show abstract

“…However, some earlier and later experimental data did not reveal the deviation of the shock Hugoniot to lower pressures [43][44][45]. Moreover, theoretical [46] and semiempirical [44,47,48] models were in better agreement with a "stiffer" curve. Finally, precise measurements of shock compression of Al at the Z-machine facility in Sandia National Labs [49] confirmed a smooth curve without any breaks while QMD simulation of shock Hugoniot of Al [48,50] turned out to be in excellent agreement with experimental data (figure 4).…”

Section: Resultsmentioning

confidence: 91%

Influence of shell effects on thermodynamic properties of matter at high pressures

Levashov

Minakov

2018

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Abstract. We analyze the influence of shell effects on thermodynamic properties of matter at high pressures. Spherically symmetric average atom models show significant contribution of electronic transitions to cold pressure which is not confirmed by more accurate density functional theory models. In particular, the s-d transition in aluminum and potassium does not reveal itself on the shock Hugoniots. Oscillations on shock Hugoniots at very high pressures predicted earlier by many authors should be confirmed by precise first-principle calculations. IntroductionThermodynamic properties of matter at high pressure are of importance in many problems of high energy density physics, in particular, in astrophysics [1], in wide-range equations of state [2,3], in the problems of interaction of intense energy fluxes with matter [4-6], in perspective power generation facilities [7] and in some others. The finite-temperature Thomas-Fermi (TF) model [8] based upon semiclassical approximation is widely used to describe thermodynamic properties of matter, but there are many phenomena beyond this approach. In particular, shell effects reflect non-regularities of physical parameters because of the discrete energy spectrum. For example, in low-density plasma step-wise dependencies of thermodynamic functions on isochors or isobars are quite typical [9]. The other well-known effect is connected with the non-regular behavior of density of elements vs. atomic mass [10,11]. To describe shell effects one should take into account discrete energy levels. Analytically shell corrections to the TF model have been studied in [12,13] using the Poisson formula in the transition from summation to integration (see also the review [14]). Average atom models [15][16][17][18][19] are based on a radial solution of the single-particle Schrödinger (Dirac) equation so that the discrete spectrum and shell effects are taken into account implicitly. During the last 30 years it became possible to obtain approximate three-dimensional (3D) solutions of a quantum many-particle problem using density functional theory (DFT) [20,21]. In this case one gets a 3D band structure of a system of particles that provides for the appearance of shell effects through non-regularities of the electronic density and some thermodynamic functions. There were several attempts to register shell effects at high pressures and temperatures experimentally [22][23][24] using underground nuclear explosions. It is claimed [24] that the influence of the discrete energy spectrum is

show abstract

“…The initial parameters were chosen to be equal to the normal conditions: P 0 = 1 bar, 1/V 0 = ρ 0 = 2.71 g/cm 3 and E 0 = −3.607 eV per atom (the last value was calculated by QMD at V = V 0 and T = 293 K). For porous samples we replace V 0 in (1) [7] based upon the model [8] for Al.…”

Section: Calculationsmentioning

confidence: 99%

“…Its thermodynamic properties have been investigated in numerous static and dynamic experiments and explored with the use of modern theories as well. Nevertheless, the EOS for aluminum is still an urgent problem in the physics of high energy densities [1][2][3]. The reason is the uncertainty in experimental data at pressures about 2.3 Mbar, as well as the fact that the region of higher temperatures and pressures is still poorly explored [3].…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the EOS for aluminum is still an urgent problem in the physics of high energy densities [1][2][3]. The reason is the uncertainty in experimental data at pressures about 2.3 Mbar, as well as the fact that the region of higher temperatures and pressures is still poorly explored [3]. Besides, this metal is convenient for simulations because of a small number of valent electrons (only 3) and a weak influence of core electrons even at high pressures and temperatures [4].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation