Impact fragmentation and ballistics of pressed aluminum powder projectiles

The penetration and fragmentation characteristics of spheres made of pressed aluminum powder are studied via normal impact on thin steel plates at 0.6 to 2.5 km/s. Ultra-high speed photography and flash x-rays are used to monitor the formation and evolution of the debris cloud formed by impact. The mass distribution of debris fragments is measured directly via a soft-catch experiment. Experimental results are compared to simple analytic theories of brittle fragmentation and spall. Additional experiments in which the debris is allowed to strike a thick steel anvil result in significant energy release via particle combustion. This data aids in understanding the mechanical properties and potential energy release of porous reactive materials.