Abstract
Targets made of aluminum alloy 5056 were subjected to hypervelocity impacts (HVI) from high-purity fused quartz (SiO2) projectiles at impact velocities of 0.8 to 3.4 km/s. The effect of the impact velocity on crater shape was examined experimentally, and the Vickers hardness was measured near the crater wall. These results were compared with the results for other brittle projectiles, such as soda-lime glass spheres and NaCl projectiles. The ratio of the crater depth to the crater diameter, expressed as a function of the impact velocity, showed anomalous humps below 2.2 km/s and a steady state above 2.2 km/s. Humps in this ratio were originally observed by Baker, Bernhard and Hörz in 1995. In 2004, Valerio-Flores et al. showed that the steady state value of this ratio varied between 0.5 and 1.2 for projectile densities ranging from 2.3 to 15 g/cm3. Our results were good agreement with these results. The relationships among projectile fragmentation, phase transition, and crater formation were discussed.
