Design of a Three-Layer Impactor for Material Strength Measurements at Multi-Megabar Pressures

Autor: Wehrenberg, C., Barmore, L. M., Volz, T. J., Ambrose, P., Rhee, M., Chau, R., Brown, J., Ali, S. J., Eggert, J. H., Fratanduono, D.
Zdroj: Journal of Dynamic Behavior of Materials; 20240101, Issue: Preprints p1-6, 6p
Abstrakt: Off-Hugoniot loading methods for dynamic compression have been a topic of interest for many years as a means of accessing high pressures without melting a material. Simulations and an initial test experiment of a three-layer gas-gun impactor suitable for use in measuring dynamic material strength at multi-megabar pressures are described. As shown through ARES hydrocode simulations, an impactor consisting of a low-, medium-, and high-impedance material, such as TPX, Al, and Ta or Pt, can produce a quasi-isentropic loading path up to 4.6 Mbar pressure with a low homologous temperature (T/Tmelt= 0.1–0.25). These impactors can also be tailored to create a pressure drive suitable for a Lagrangian sound speed experiment. Simulated in-situ velocities were analyzed to determine the change in calculated strength due to non-uniformity in the impactor, which provides a measure of error sensitivity. An initial test of a three-layer projectile onto a flat target at 4.4 km/s impact velocity is reported. While the impactor incurred some delamination during firing, the measured sample/window interface velocity generally agrees with the simulated peak velocity and subsequent release, indicating the feasibility of this approach for measuring material strength.
Databáze: Supplemental Index
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