Extraordinary Increase in Dynamic Strength of Platinum at 430 GPa without Phase Transformation Observed at the National Ignition Facility

The high-pressure strength of solid platinum is studied at the National Ignition Facility via Rayleigh-Taylor ripple growth under ramp compression. Laser-driven experiments reached pressures up to 430 GPa, collecting velocimetry and radiography data. The observed ripple growth aligns with hydrodynamic simulations using an amplified Steinberg-Guinan model, resulting in a 200-fold increase in strength despite no phase transformation. Molecular dynamics simulations of platinum ramp compression yielded similar von Mises stress at high pressure. These findings offer critical insights into the significant strengthening of platinum under high pressure and strain rate conditions. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.