Intermetallic Compounds

The attractive physical and mechanical properties of ordered intermetallic alloys have been recognized since early in this century. However, periodic attempts to develop intermetallics for structural applications were unsuc cessful, due in major part to the twin handicaps of inadequate low-temper ature ductility or toughness, together with poor elevated-temperature creep strength. The discovery, in 1979, by Aoki and Izumi in Japan that small additions of boron caused a dramatic improvement in the ductility of Ni3Al was a major factor in launching a new wave of fundamental and applied research on intermetallics. Another important factor was the issuance in 1984 of a National Materials Advisory Board reported entitled "Structural Uses for Ductile Ordered Alloys," which identified numerous potential defense-related applications and proposed the launching of a coordinated development program to gather engineering property and processing data. A substantial research effort on titanium aluminides was already underway at the Air Force Materials Laboratory at Wright Patterson Air Force Base in Ohio and, with Air Force support, at several industrial and university laboratories. Smaller programs also were under way at Oak Ridge National Laboratory, under Department of Energy sponsorship. These research efforts were soon augmented in the United States by funding from Department of Defense agencies such as Office of Naval Research and Air Force Office of Scientific Research, and by the National Science Foundation.

An intermetallic compound is one consisting of two or more metallic elements present in definite proportions in alloy. They are used in a wide range of industries such as semiconductors and the aerospace industry. Thousands of tons of the nickel aluminum alloy are used worldwide every year.

Intermetallic compounds are usually brittle with high melting points. Their properties are often found among ceramic and metallic materials. In most cases, their hot corrosion resistance and simultaneously hardness are important. One of the main applications of intermetallic compounds is for superalloy turbine blades in which they show appropriate high-temperature-related properties. This book collects new developments about intermetallic compounds and their recent usages.

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.

Intermetallic Compounds in Mercury is Volume 51 of the Solubility Data Series. It follows Volume 25, Metals in Mercury, of the same series. Evaluations of more than fifty systems are presented together with all of the data and citations from the original literature. In addition, over 200 references are given to related literature that describes metal interactions in amalgams but from which quantitative information can only be inferred. For each compound reported, a critical evaluation presents recommended or tentative values of solubilities or solubility products based on statistical treatment of the data reported. Mercury provides a unique solvent for metal-metal reactions, and thus the data reported here are a valuable addition to the experimental basis for better fundamental understanding of interactions of metals in the elemental state. In addition, this material is important technologically in the areas of metal processing, materials, and electrochemistry.

The topic of hydrogen in an on metals and alloys is important in a number ofdisciplines including solid-state physics, materials science, physical chemistry, and energy technology. This volume treats the dynamics of hydrogen in intermetallic compounds, surface properties, kinetics, and applications of metal hydrides in energy technology. In addition, selected experimental methods are described. The introductory chapter will enable non-specialists to gain an overall picture of the field and to appreciate the relevant scientific issue. The companion volume, Hydrogene in Intermetallic Compounds I, was published as Vol. 63 of Topics in Applied Physics.