Materials Modification and Synthesis Under High Pressure Shock Compression

There is currently a surge of interest in the use of high pressure shock compression to synthesize materials or to modify microstructure to achieve unique properties. This new thrust has developed from well-established knowledge of the physical and mechanical effects associated with shock compression, from new programs underway to study chemistry under shock compression, and from successful examples of industrial shock processing. Work in this area may prove technologically significant ; but whether or not any significant material applications result, it is certain that the work will extend our knowledge of material responses and material properties into regimes not previously explored. The high pressure, rapid material motion, intense plastic deformation (even in conventionally brittle materials), high temperature, and short duration of the shock event force matter through a unique process. To the extent that synthesis can occur in the microsecond duration of the high pressure pulse, chemical processing can be carried out in large volumes at extraordinarily high pressure. High pressure processing not only opens the door to new reactions but provides the opportunity to involve dense-phase polymorphs in reactions. Quenching of pressure and temperature from transient states permits formation of metastable states. High concen-