Extreme Hardening of Pb at High Pressure and Strain Rate

We study the high-pressure strength of Pb and Pb-4wt%Sb at the National Ignition Facility. We measure Rayleigh-Taylor growth of preformed ripples ramp compressed to ∼400 GPa peak pressure, among the highest-pressure strength measurements ever reported on any platform. We find agreement with 2D simulations using the Improved Steinberg-Guinan strength model for body-centered-cubic Pb; the Pb-4wt%Sb alloy behaves similarly within the error bars. The combination of high-rate, pressure-induced hardening and polymorphism yield an average inferred flow stress of ∼3.8 GPa at high pressure, a ∼250-fold increase, changing Pb from soft to extremely strong.Received 26 February 2019DOI:https://doi.org/10.1103/PhysRevLett.123.205701© 2019 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCompressive strengthDynamical phase transitionsPlastic deformationPressure effectsTechniquesX-ray imagingCondensed Matter, Materials & Applied Physics