Equation of state of Al, Cu, Mo, and Pb at shock pressures up to 2.4 TPa (24 Mbar)

Abstract

Equation-of-state data and corresponding first-principles theory for the metals Al, Cu, Mo, and Pb are reported over the shock pressure range 0.4–2.4 TPa (4–24 Mbar). Strong shock waves were generated by nuclear explosions and a two-stage light-gas gun. The experimental data occur in the hot liquid-metal regime, where condensed-matter theory applies but with unusually large thermal components to the equation of state.

Global equation of state for copper

“…Fig. 3 demonstrates the accuracy of the current EOS compared to principal Hugoniot data [1][2][3][4][5]. In Fig.…”

“…Thermophysical properties of copper have been reported extensively including the principal Hugoniot [1][2][3][4][5], thermal expansion [6], roomtemperature isotherm [7,8], and heat capacity [9][10][11], making copper a well-characterized material and a suitable standard in many experiments. As a result, a highly accurate equation of state is needed to describe the behavior of the material over a large range of conditions [12][13][14][15].…”

Shock Hugoniot of single crystal copper

“…4. The single crystal data from this study are plotted against the previous polycrystalline data of Mitchell et al for comparison [6]. The inset shows the current single crystal data in comparison to the polycrystalline data of Mitchell et al The error bars for the single crystal data are obtained using the error analysis as described in Ref.…”

“…Using simple arguments, Bringa and co-workers suggested that a strong crystal orientation dependence would appear in both the elastic and plastic waves in Cu [4]. Using molecular dynamics (MD) simulations, Bringa et al [4] show a distinct deviation of the Hugoniot from the experimental polycrystalline data of Mitchell et al [6]. The calculated Hugoniot curves (shock velocity, U s , versus mass velocity, U p ) for the three crystalline directions investigated converge to the polycrystalline curve with increasing U p but show distinct deviations from the linear fit of the polycrystalline data at lower values of U p .…”

“…These experiments were performed in the range of stresses between 9 and 67 GPa that corresponds to the regime predicted by the two simulation studies to exhibit strong orientation dependence. The upper end of that stress range was chosen to overlap the lowest stresses measured on polycrystalline Cu [6].…”