Near-Optimal Combination of High Performance and Insensitivity in a Shock Compressed High Explosive Single Crystal

Achieving the desired combination of superior detonation performance and insensitivity to shock initiation has been a long-standing goal in high explosive (HE) science and technology. Having previously established the shock insensitivity of 1,1-diamino-2,2-dinitroethene (FOX-7) single crystals to 20 GPa (extended to 25 GPa in this work), the FOX-7 detonation response was determined through wave profile measurements in ~250 µm thick single crystals shock compressed to 64 GPa. Quite unexpectedly, FOX-7 demonstrated classic Chapman-Jouget (C-J) detonation response – reaction completion in the detonation front (<0.7 ns) at pressures of 44 GPa and higher – not observed in other insensitive high explosives (IHEs). Sound speeds in the compressed detonation products were determined from the measured wave profiles, enabling experimental determination of the C-J state for FOX-7 single crystals. The experimentally determined C-J pressure (35 GPa), detonation wave velocities, and the detonation products equation of state – together with shock insensitivity to 25 GPa – demonstrate that FOX-7 single crystals display a near-optimal combination of high performance and shock insensitivity, not observed in any other HE crystal.