Thursday  |  Monongahela  |  01:50 PM–02:10 PM

#13800, Strength at 10^7 /sec Strain Rate in Beta Phase Tin from Richtmyer-Meshkov Instability Experiments

Impact-driven free-surface Richtmyer-Meshkov Instability (RMI) experiments were performed on tin at shock stresses of 4 and 6 GPa to study strength in the ambient beta phase. Each experiment included three different perturbation sizes, with the non-dimensional amplitude h0k ranging from 0.4 – 1.2 for the 4 GPa shot and 0.3 – 1.0 for 6 GPa. The perturbation wavelengths were all 0.2 mm. Photon Doppler Velocimetry (PDV) was used to measure velocities as the perturbation low points inverted into “spikes.“ The maximum spike velocities were used along with hydrocode modeling to estimate average strength. The models indicate effective strain rates from 3 × 10^6 /sec for the smallest perturbation at 4 GPa to more than 3 × 10^7 /sec for the largest perturbation at 6 GPa. The estimated strengths, at well under 1 GPa, are modest for a metal at such high strain rates and are lower than many model predictions that extrapolate to this regime. These free-surface RMI experiments exercise strength at low pressures and provide a unique opportunity to isolate strain rate effect from high pressure effects in such extreme conditions.

Michael Prime   Los Alamos National Laboratory
Saryu Fensin   Los Alamos National Laboratory
David Jones   saryuj@lanl.gov
Patrick Donovan   Los Alamos National Laboratory
Joshua Dyer   Los Alamos National Laboratory
Calvin Lear   Los Alamos National Laboratory
Kevin Love   Los Alamos National Laboratory
Daniel Martinez   Los Alamos National Laboratory