Improved Richtmyer-Meshkov Instability Experiments for Very-High-Rate Strength and Application to Tantalum

Recently, Richtmyer-Meshkov instabilities (RMI) have been used for studying metal strength at strain rates up to at least 10^7/s. RMI experiments involve shocking a metal interface with geometrical perturbations that invert, grow, and possibly arrest subsequent to the shock. In experiments one measures the growth and arrest velocities to study the specimen’s flow (deviatoric) strength. In this paper, we describe experiments on tantalum at three shock pressure from 20 to 34 GPa, with six different perturbation sizes at each pressure, making this the most comprehensive set of RMI experiments on any material. In addition, these experiments were fielded using impact loading, as compared to high explosive loading in previous experiments, allowing for more precise modeling and more extensive interpretation of the data. Preliminary results are presented.