Evolution of shock wave in pure aluminum and annealed Al 6061 alloy at temperatures 300 K (a), 932 K (b) and 800/851 K (c). The temperature 851 K chosen for the alloy is some 4 K below its solidus temperature . Arrows show the velocities corresponding to the material Hugoniot elastic limit and the spall-related velocity pullback .
Hugoniot elastic limit (filled triangles), yield stress (diamonds), and the spall strength (circles) as a function of the temperature after experiments with 2-mm samples of pure aluminum. The values determined based on the “spike” values using Eq. (4) are shown by open triangles.
Maximum steepness of the plastic shock front in aluminum (the same 2-mm samples as in Fig. 2) as a function of initial sample temperature.
Stress at HEL of pure aluminum as a function of the propagation distance at different initial temperatures (shown next to the corresponding dependence).
Parameters and of the Eq. (6) for pure aluminum as a function of the initial sample temperature. The dashed lines correspond to the fits (7) and (8).
Decay of elastic precursor wave in annealed 6061 aluminum at room temperature and 851 K (circles) in comparison with decay in pure aluminum at the same temperatures. The dash-dotted line presents the approximation of the entire volume of the data for various aluminums (Ref. 10).
The shear stress at HEL as a function of plastic strain rate in pure aluminum shocked from different initial temperatures (shown at the right edge of the plot). Upward and downward triangles correspond to the points for 0.1-mm and 2-mm sample thickness, respectively. The small squares with error bars are the points corresponding to the mid-height of the plastic shock wave.
Temperature dependences of the shear stress behind the elastic precursor front obtained from the data shown in Fig. 7 at three fixed strain rates.
Density of mobile dislocations in pure aluminum as a function of plastic strain rate . The straight lines are the dependences calculated using Eq. (12). For clarity, the lines corresponding to the lowest and the highest values of initial temperatures are shown by arrows. The downward triangles correspond to the values just behind the elastic precursor shock in 2-mm samples. As in Fig. 7, the small squares with error bars are the estimates of the density of mobile dislocations corresponding to the maximum strain rate in the plastic shock wave.
Parameters of planar impact experiments with pure aluminum and 6061 aluminum alloy.
Parameters and α of Eqs. (7) and (8) and factor of Eq. (9) at different temperatures.
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