The Role of Shock Wave Compression in Materials Science

Abstract

Shock wave compression technology has contributed much to the progress of materials science. The present author has tried to discuss the role of shock wave techniques with respect to very high pressure materials science studies. Shock wave techniques also unique very high temperature methods. The important role of shock wave technology seems to be the attainment of pressures above those which can be obtained by static techniques. A typical example is equation of state studies done up to pressures of a few megabars. Recently, a static technique utilizing a small pair of diamond anvils has been established which is capable of attaining a few megabar pressures. This technique is performing the majority of equation of state studies. Shock wave compression is accompanied by high shock temperature. Recently, new dynamic compression techniques, which are isentropic-like, are being developed and applied to equation of state studies. On the other hand, several shock studies suggested that due to the very high shock temperatures, accompanying shock compression, dynamic compression techniques could be utilized as a unique high temperature method. High inhomogeneous shock temperatures can be produced in porous and/or compressible materials during strong shock compression. These temperatures induce local melting and ionization. It is expected that a high dense plasma-like state is formed in extremely strong shock wave compression. After passage of the shock wave, the materials cool rapidly during pressure release to a residual temperature and pressure. Occasionally the materials recovered after having been converted to a dense liquid or gas state showed very unique microstructures. The present author believes that more precise, compact and easily operative shock wave compression apparatus should be developed and made available to general material scientists and engineers.