Dislocation characteristics in energetic crystals

Armstrong, Ronald W.; Elban, Wayne L.
April 2000
AIP Conference Proceedings;2000, Vol. 505 Issue 1, p723
Academic Journal
The combination of weak intermolecular solid-state bonding of oddly-shaped energetic molecules and their packing into low symmetry lattice structures leads to expectation of a significant variation in dislocation Burgers (displacement) and line vectors, counterbalanced by the occurrence of low dislocation densities that are attributed to relatively high self-energies. Such reasoning is demonstrated to be the case from x-ray topography and chemical etch-pitting observations made on solution-grown crystals. Modeled dislocation movement is shown to be difficult at the crystal lattice level because of intermolecular cross-blockages of adjacent juxtaposed molecules that relate to detection of deformation and thermally-induced molecular fragmentations. These results are in agreement also with evaluation of microindentation measurements put onto a hardness stress-strain description of the overall crystal elastic, plastic and cracking behaviors. On the larger microscopic scale, dislocation pile-ups in energetic materials are shown to be capable of producing very significant "hot spot" heating, this too in agreement with measurements of increased crystal drop-weight heights being required for initiation of smaller crystals.


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