Dynamic compaction of ceramic powders

Dynamic consolidation is a technique for densifying powder ensembles to near theoretical with or without external application of heat. The technique itself is simple: the confined powder, initially at a green density of similar to 50%, encounters a high pressure shock wave which exceeds the yield strength and densifies as the wave proceeds through the compact. The time scales and pressure range from 1-10's of microseconds and 10-100's of kilobars (10 Kb = 1 GPa). The short time scale of the pressure pulse during the compaction stage inhibits kinetic processes which have longer time constants. The pressure pulse can be delivered to the green compact by a number of techniques, i. e. high explosive, projectile. The methods differ in the degree that one can control the amplitude, duration, and nature of the pressure pulse. The paper will compare powders compacted by explosive and light gas guns and when possible characterize their resulting structures and properties.