We demonstrate a strongly thresholded response in cyclotrimethylene trinitramine (RDX) when it is cylindrically shocked using a novel waveguide geometry. Using ultrafast single-shot multi-frame imaging, we demonstrate that <100-{\mu}m diameter single crystals of RDX embedded in a polymer host deform along preferential planes for >100 ns after the shock first arrives in the crystal. We use in-situ imaging and time-resolved photoemission to demonstrate that short-lived chemistry occurs with complex deformation pathways. Using scanning electron microscopy and ultrasmall-angle X-ray scattering, we demonstrate that the shock-induced dynamics leave behind porous crystals, with pore shapes and sizes that change significantly with shock energy. A threshold pressure of ~ 12 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 directions for deformation for our cylindrically shocked system, despite the applied stress along many different crystallographic planes.
@article{arxiv.1908.03785,
title = {Pressure-Thresholded Response in Cylindrically Shocked Cyclotrimethylene Trinitramine (RDX)},
author = {Leora E. Dresselhaus-Cooper and Dmitro Martynowych and Fan Zhang and Charlene Tsay and Jan Ilavsky and SuYin Grass Wang and Yu-Sheng Chen and Keith A. Nelson},
journal= {arXiv preprint arXiv:1908.03785},
year = {2020}
}