A concept of reactive hot spots intruded in a base structural reactive material (SRM) casing was investigated to generate fine primary or secondary fragments for efficient energy release from thick casing material under explosive loading. This was achieved through distributing micro-scale reactive material particles into base SRM in a fuel-rich equivalence ratio. Reaction of these particles during SRM primary or secondary fragmentation creates heat and gas products to form micro-scale hot spots, whose expansion initiates local fractures leading to fine SRM fragments. Test casings 7.62 cm in inner diameter were made using micro-scale Al-CuO as hot spot material distributed in base Al through cold gas dynamic spray deposition technology, which reached a yield stress of 200 MPa. Explosion experiments were conducted in a 3 m diameter, 23 m3 cylindrical chamber for these cased charges in a casing-to-explosive mass ratio of 1.76. The results demonstrated more efficient fragment combustion leading to a 50% increase in blast front pressure in early time and a 17% increase in quasi-static pressure late in times, versus pure Al-cased charges, thus indicating the feasibility of the concept.
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