The Wormholes Within: A Study of 1, 3, 5‐Triamino‐2, 4, 6‐Trinitrobenzene Crystal Morphology by Micro and Nano‐Scale X‐Ray Computed Tomography and its Effects Upon the Shock Sensitivity of Detonation

Abstract

AbstractWe understand heterogeneous‐explosive detonation only to the extent that we can first measure the salient chemical and microstructural features. Barring an inordinate amount of trial and error, we can tailor the detonation properties of our HE formulations only to the extent that we understand (at least qualitatively) the same effects. As an insensitive high explosive, 1, 3, 5‐triamino‐2, 4, 6‐trinitrobenzene (TATB) burns more heterogeneously than conventional high explosives, making its detonation properties sensitive to microstructure. The Benziger route can produce various grain morphologies depending on the amount of water used in the amination step. So‐called dry‐aminated (DA) TATB crystals are riddled with a void structure called wormholes, which are washed out ammonium chloride (NH4Cl) inclusions that form during synthesis. So‐called wet‐aminated (WA) TATB crystals do not contain NH4Cl inclusions but possess a very convoluted external structure. Using both micro and nano‐scale CT, we explore three DA‐TATB lots that reflect evolutionary processing changes, plus one WA‐TATB material. Micro CT imaged crystal collections show the exterior grain structure, revealing its roughness and providing a crude particle size measurement. The DA‐TATB lots that test most sensitively in the LANL ECOT corner‐turning test are roughest, having the appearance of being “corroded”. Nano‐scale CT reveals both internal NH4Cl inclusions and void structures. The DA‐TATB lots that tested intermediate and high sensitivity in ECOT exhibited similar wormhole structures, which were more extensive than that of the low‐sensitivity lot. The least sensitive DA‐TATB lot also retained more NH4Cl, consistent with reduced connectivity of voids to the surface.