Equations of State of Selected Armor Ceramics by In-situ High-Pressure X-ray and Ultrasonic Techniques: Comparison with Shock Wave Data

Ultrasonic measurements of the sound velocity and elastic moduli, and their pressure derivatives for well prepared armor ceramics can provide accurate constraints for establishing their equations of state. Using in-situ high-pressure synchrotron X-ray diffraction and diamond anvil cell techniques at the Advanced Photon Source, we have investigated the compression behavior ($V$/$V_{o}$ vs $P)$ for $\alpha$- and $\beta$-SiC, TiB$_{2}$, B$_{4}$C, WC and WC-6{\%}Co to 65 GPa. Ultrasonic measurements of K$_{o}$ and K$_{o}\prime$ made to $\sim$15 GPa show excellent agreement with X-ray results. Together, these results are compared with published shock wave data in terms of U$_{s}$-U$_{p}$ slope, K$_{o}\prime $, compression behavior, elastic anisotropy, and material strength. No phase transition is found in these materials, except for B$_{4}$C, in which case some structural distortion is indicated.