Pressure-Thresholded Response in Cylindrically Shocked Cyclotrimethylene Trinitramine (RDX)
Leora E. Dresselhaus-Cooper, Dmitro Martynowych, Fan Zhang, Charlene Tsay, Jan Ilavsky, SuYin Wang, Yu-Sheng Chen, Lara Leininger, Keith A. Nelson
We demonstrate a strongly thresholded response in cyclotrimethylene trinitramine (RDX) that is cylindrically shocked using a novel waveguide geometry. Using ultrafast single-shot multi-frame imaging, we demonstrate that a ~100-μm diameter single crystal of RDX embedded in a polymer host deforms along preferential planes for >100 ns after the shock first arrives in the crystal. In- situ, we use imaging and time-resolved photoemission to demonstrate that short-lived chemistry is linked to high-energy deformation planes. Using scanning electron microscopy and ultra-small angle X-ray scattering, we demonstrate that the shock-induced dynamics leave behind sintered crystals, with pore shapes and sizes that change significantly with shock energy. A threshold pressure of 10 GPa at the center of convergence separated the single-mode planar crystal deformations from the chemistry-coupled multi-plane dynamics at higher pressures. Our observations indicate preferential deformation mechanics in our cylindrically shocked system, despite the applied stress along many different crystallographic planes, demonstrating inherent sensitivity in the molecular crystals.