The density-functional formalism is used as the framework within which to assess previous calculations and to suggest new avenues of research. As a result of the study, we judge that significant results should be obtained from theoretical high-pressure-physics investigations at one of three levels of sophistication: the Gordon-Kim-Boyer scheme with our suggested modifications; use of the exchange-correlation potential in the local-density approximation in such an accurate band-structure calculation as the augmented-plane-wave, Korringa-Kohn-Rostoker, or linear-combination-of-muffin-tin-orbital methods; or a complete calculation of the electron dynamics in the local-density approximation, which would also be useful in calculating the phonon spectrum. This approach should yield good results for the equation of state, which is the required basis for studies of dynamic and nonlinear effects, structural transitions in insulators and semiconductors (possibly providing a microscopic understanding of the successful ionicity scale of Phillips), simple insulator-metal transitions, polymorphic transitions in metals, and mixed-valence salt transitions. The state of the art in experimental and theoretical high-pressure physics research is surveyed in the context of recent studies on iodine, xenon, and cesium. Ultrahigh-pressure methods now under development are also reviewed. (Author).

On October 3, 1963, a symposium was sponsored by the Bureau of Naval Weapons, Metalworking Processes and Equipment Program, on the application of high pressure in metal-deformation processing. Past research has shown that superimposed hydrostatic pressure can significantly increase the ductility at fracture of various materials. These observations have stimulated considerable interest in applying this hydrostatic-pressure effect to metal deformation processing, where it was anticipated that improved ductility and fabricability of brittle materials could be realized. Hydrostatic extrusion and hydrodynamic compressive forging were two such fabrication techniques discussed at the symposium, and preliminary results were found to be encouraging. Another fabrication process that will be investigated in the near future is sheet drawing, where the effect of superimposed pressure improves the ductility to fracture, it was noted that pressure cycling did not improve either the strength or ductility of steels containing various amounts of carbon. In addition to the mechanical-property effects, hydrostatic pressure has been found to affect measurably, numerous metallurgical properties of metals and alloys. (Author).

Presenting some of the most recent results of Russian research into shock compression, as well as historical overviews of the Russian research programs into shock compression, this volume will provide Western researchers with many novel ideas and points of view. The chapters in this volume are written by leading Russian specialists various fields of high-pressure physics and form accounts of the main researches on the behavior of matter under shock-wave interaction. The experimental portions contain results of studies of shock compression of metals to high and ultra-high pressure, shock initiation of polymorphic transformations, strength, fracture and fragmentation under shock compression, and detonation of condensed explosives. There are also chapters on theoretical investigations of shock-wave compression and plasma states in regimes of high-pressure and high- temperature. The topics of the book are of interest to scientists and engineers concerned with questions of material behavior under impulsive loading and to the equation of state of matter. Application is to questions of high-speed impact, inner composition of planets, verification of model representations of material behavior under extreme 1oading conditions, syntheses of new materials, development of new technologies for material processing, etc. Russian research differs from much of the Western work in that it has traditionally been wider-ranging and more directed to extremes of response than to precise characterization of specific materials and effects. Western scientists could expect to benefit from the perspective gained from close knowledge of the Russian work.

High pressure science is a rapidly growing diverse fi. e1d. The high pressure technique has become a powerful tool for both the study and preparation of materials. In spi. te of the many high pressure conferences held in recent years, I felt that there was a need for scientists within a well-defined area (not bound merely by the common experimental technique) to meet in an atmosphere conducive to frank exchange and close interaction. In this spirit, the Cleveland State University hosted such a conference from July 20 to 22, 1977, in which the physics of solids under high pressures and at low tempera tures was specifically examined. Both the original and review papers presented at the conference and the candid discussions following their presentations appear in this volume. They clearly cover a rather complete spectrum of current research in the physics of solids at high pressures and low temperatures. I wish to thank the National Aeronautics and Space Administra tion, the Office of Naval Research and the National Science Founda tion for their financial support of the conference. In addition, I wish especially to thank Steinar Huang for his unceasing assistance in arranging this conference. I also wish to thank him and Francis Stephenson for their assistance in preparing this book. C. W. Chu, Chairman, International Conference on High Pressure and Low Temperature Physics v Contents HYDROGEN AND METAL-HYDRIDES (Chairman: I. Spain) PROSPECTS FOR METALLIC HYDROGEN 1 A. L.