Comparison of dynamic compression behavior of single crystal sapphire to polycrystalline alumina

Due to the considerable interest in the shock loading behavior of aluminum oxide whether it is in the polycrystalline phase or in the single crystal phase well-controlled experiments were conducted to probe differences in shock loading behavior between these two materials. Previous studies concluded that the behavior was similar but careful examination of well-controlled experiments has revealed the two materials are different.Although the experimental results appear to have the same behavior in the shock velocity vs. particle velocity plane, they are considerably different in the stress-volume compression plane and evidence is provided that indicates the single crystal remains crystalline up to the stresses imposed for this analysis. This is an extremely interesting observation since it has many implications including developing dynamic material models capable of transitioning between individual grains and polycrystalline material. (C) 2010 Published by Elsevier Ltd.