AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
Exploding foil techniques were used to accelerate a Mylar flyer at a controlled velocity to produce a plane, longitudinal shock wave in 6061-T6 aluminum, and the interaction of the wave with the target free surface was studied. Flyer velocity and planarity were determined by high-speed, photographic techniques. The spall threshold was determined as a function of flyer velocity and thickness. A criterion was formulated to predict the spall threshold. Microscopic analyses revealed the mechanism of incipient spall in 6061-T6 aluminum to be cracks which propagated from inclusions in the matrix material.