It is well known that the density of molecular hydrogen can be increased by compression and/or cooling, the ultimate limit in density being that of liquid hydrogen. It is less well known that hydrogen densities of twice that of liquid hydrogen can be obtained by intercalating hydrogen gas into metals. The explanation of this unusual paradox is that the absorption of molecular hydrogen, which in TiFe and LaNis is reversible and occurs at ambient temperature and pressure, involves the formation of hydrogen atoms at the surface of a metal. The adsorbed hydrogen atom then donates its electron to the metal conduction band and migrates into the metal as the much smaller proton. These protons are easily accomodated in interstitial sites in the metal lattice, and the resulting metal hydrides can be thought of as compounds formed by the reaction of hydrogen with metals, alloys, and intermetallic compounds. The practical applications of metal hydrides span a wide range of technologies, a range which may be subdivided on the basis of the hydride property on which the application is based. The capacity of the metal hydrides for hydrogen absorption is the basis for batteries as well as for hydrogen storage, gettering, and purification. The temperature-pressure characteristics of metal hydrides are the basis for hydrogen compressors, sensors, and actuators. The latent heat of the hydride formation is the basis for heat storage, heat pumps, and refrigerators.

It is well known that the density of molecular hydrogen can be increased by compression and/or cooling, the ultimate limit in density being that of liquid hydrogen. It is less well known that hydrogen densities of twice that of liquid hydrogen can be obtained by intercalating hydrogen gas into metals. The explanation of this unusual paradox is that the absorption of molecular hydrogen, which in TiFe and LaNis is reversible and occurs at ambient temperature and pressure, involves the formation of hydrogen atoms at the surface of a metal. The adsorbed hydrogen atom then donates its electron to the metal conduction band and migrates into the metal as the much smaller proton. These protons are easily accomodated in interstitial sites in the metal lattice, and the resulting metal hydrides can be thought of as compounds formed by the reaction of hydrogen with metals, alloys, and intermetallic compounds. The practical applications of metal hydrides span a wide range of technologies, a range which may be subdivided on the basis of the hydride property on which the application is based. The capacity of the metal hydrides for hydrogen absorption is the basis for batteries as well as for hydrogen storage, gettering, and purification. The temperature-pressure characteristics of metal hydrides are the basis for hydrogen compressors, sensors, and actuators. The latent heat of the hydride formation is the basis for heat storage, heat pumps, and refrigerators.

This book provides the foundations of understanding the physical nature of iron and its alloys. Basics and recent developments concerning its constitution and magnetism are presented as well as its thermal properties.

Complex metal alloys (CMAs) comprise a huge group of largely unknown alloys and compounds, where many phases are formed with crystal structures based on giant unit cells containing atom clusters, ranging from tens of to more than thousand atoms per unit cell. In these phases, for many phenomena, the physical length scales are substantially smaller than the unit-cell dimension. Hence, these materials offer unique combinations of properties which are mutually exclusive in conventional materials, such as metallic electric conductivity combined with low thermal conductivity, good light absorption with high-temperature stability, high metallic hardness with reduced wetting by liquids, etc.This book is the second of a series of books issued yearly as a deliverable to the European Community of the School established within the European Network of Excellence CMA. Written by reputed experts in the fields of metal physics, surface physics, surface chemistry, metallurgy, and process engineering, this book brings together expertise found inside as well as outside the network to provide a comprehensive overview of the current state of knowledge in CMAs.

High-Entropy Alloys, Second Edition provides a complete review of the current state of the field of high entropy alloys (HEA). Building upon the first edition, this fully updated release includes new theoretical understandings of these materials, highlighting recent developments on modeling and new classes of HEAs, such as Eutectic HEAs and Dual phase HEAs. Due to their unique properties, high entropy alloys have attracted considerable attention from both academics and technologists. This book presents the fundamental knowledge, the spectrum of various alloy systems and their characteristics, key focus areas, and the future scope of the field in terms of research and technological applications. - Provides an up-to-date, comprehensive understanding on the current status of HEAs in terms of theoretical understanding and modeling efforts - Gives a complete idea on alloy design criteria of various classes of HEAs developed so far - Discusses the microstructure property correlations in HEAs in terms of structural and functional properties - Presents a comparison of HEAs with other multicomponent systems, like intermetallics and bulk metallic glasses

This book focuses on the role of modeling in the design of alloys and intermetallic compounds. It includes an introduction to the most important and most used modeling techniques, such as CALPHAD and ab-initio methods, as well as a section devoted to the latest developments in applications of alloys. The book emphasizes the correlation between modeling and technological developments while discussing topics such as wettability of Ultra High Temperature Ceramics by metals, active brazing of diamonds to metals in cutting tools, surface issues in medicine, novel Fe-based superconductors, metallic glasses, high entropy alloys, and thermoelectric materials.

Interstitial Alloys covers the significant progress in the development and understanding of the principles and applications of interstitial alloys. Interstitial alloy refers to the existence of a pure metal lattice, which the metal-metal atom bond remains the dominant one, and the non-metal atoms are sufficiently small to be accommodated within the metal lattice without, or with only a limited degree of, distortion from metal-type symmetry. This book contains 10 chapters and begins with a brief introduction to the basic principles of interstitial alloys. The next two chapters describe the physical properties of these alloys, along with their behavior in solid solutions. The remaining chapters deal with a specific interstitial alloy, its structure, physico-chemical properties, preparation, and application. This work specifically considers carbide, nitride, boride, silicide, oxide, hydride, and mixed interstitial alloys. This book will be of value to chemists and physicists.