Dynamic strength measurements of various metals using the Rayleigh-Taylor instability

When a light material (pusher) is accelerated toward a denser material (sample), any perturbation at their interface becomes unstable and grows in amplitude, a phenomenon known as Rayleigh-Taylor (RT) instability growth. Since the strength of both materials may influence the RT growth, knowing the strength of one material is essential for accurately measuring the absolute strength of the other. Epoxy has been historically used as a pusher material due to its lower density and assumed negligible strength, compared to metallic materials. However, our recent studies using an epoxy pusher and Sn or Cu samples revealed unexpectedly low RT growth, suggesting that epoxy strength may not be negligible under extreme conditions. Here, we investigate the RT growth of various pusher-sample pairs, composed of epoxy, Al, Sn, Cu, and Au. A low-adiabat pulse shape is designed to ramp-compress the physics package to a peak condition of 150 GPa and 1500 K. In-situ face-on x-ray radiography is utilized to measure ripple growth. Finally, hydrodynamic simulations using variations on the commonly adopted Steinberg-Guinan strength model are compared with experimental results to deconvolute their relative strengths and determine the individual materials' strengths.