Energy Release And Fragmentation Of Brittle Aluminum Reactive Material Cases

Cylindrical reactive material cases produced by the consolidation of an aluminum powder were tested via explosive launch in a closed chamber. One configuration measured the quasistatic overpressure generated by the case and explosive, and two further tests focused on soft-catch of fragments before and after striking the chamber walls. On a volumetric basis, the reactive material cases produced two to three times the combustion energy of an aluminum 6061 alloy case or a bare nitromethane explosive that was tested as comparisons. The metal combustion primarily occurs after case fragments impact the walls. Increasing the reactive material case thickness produces a higher pressure but lower combustion efficiency per unit mass, despite producing comparable or slightly more fine fragments on a per gram basis. Though the brittle, pressed aluminum cases have low toughness and tensile strength, recovered fragment patterns show a range of fragment sizes up to 1 mm, with approximately one-third of the mass below 100 mu m.