Unusual strength in tin under dynamic compression

Tin is a soft metal that undergoes several phase transitions at high pressure and temperature (1). These structural changes should lead to significant changes in both material microstructure and physical properties upon compression. Here, we use the Rayleigh-Taylor instability to measure its strength within the high-pressure BCC phase. A pre-machined rippled pattern seeds the instability, wherein a low density fluid pushing against a high density fluid causes growth of surface perturbations. We use a CH layer as the low density material, and the “push” is provided by the Omega EP laser facility, University of Rochester, which generates a ramped compression drive of ~1.5 Mbar in the sample. Ripple growth is measured using face-on radiography, and strength is interpreted based on the rate of growth relative to the undriven portion of the sample. We find that the growth rate is much less than that predicted in hydrodynamic simulations using a Steinberg-Guinan model. This suggests that BCC tin has unusually high strength, interpreted here as a resistance to plastic deformation.
Lazicki, A et al. Phys. Rev. Lett. 115, (2015).