Stiff response of aluminum under ultrafast shockless compression to 110 GPA.

A laser-produced x-ray drive was used to shocklessly compress solid aluminum to a peak longitudinal stress of 110 GPa within 10 ns. Interface velocities versus time for multiple sample thicknesses were measured and converted to stress density (Px-rho) using an iterative Lagrangian analysis. These are the fastest shockless compression Px(rho) results reported to date, and are stiffer than models that have been benchmarked against both static and shock-wave experiments. The present results suggest that at these short time scales there is a higher stress-dependent strength and a stiffer time-dependent inelastic response than had been expected.