Metallurgy overview

Physical Properties. An overview of the metallurgy (qv) and soUd-state physics of the rare earths is available (6). The rare earths form aUoys with most metals. They can be present interstitiaUy, in soUd solutions, or as intermetaUic compounds in a second phase. Alloying with other elements can make the rare earths either pyrophoric or corrosion resistant. It is extremely important, when determining physical constants, that the materials are very pure and weU characteri2ed. AU impurity levels in the sample should be known. Some properties of the lanthanides are Usted in Table 3. 

The study of microstructures in relation to important properties of metals and alloys, especially mechanical properties, continues apaee. A good overview of eurrent concerns can be found in a multiauthor volume published in Germany (Anon. 1981), and many chapters in my own book on physieal metallurgy (Cahn 1965) are devoted to the same issues. 

The kinetics of diffusion-controlled phase transformations has long been a focus of research and it is vital information for industrial practice as well as being a fascinating theme in fundamental physical metallurgy. An early overview of the subject is by Aaronson et ai (1978). 

According to an early historical overview (Jones 1960), the numerous attempts to understand the sintering process in both ceramics and metals fall into three periods (1) speculative, before 1937 (2) simple, 1937-1948 (3) complex, 1948 onwards. The complex experiments and theories began just at the time when metallurgy underwent its broad-based quantitative revolution (see Chapter 5). 

In this chapter, we survey the diversity of transition metals, beginning with an overview. Then we describe the stmcture and bonding in transition metal complexes. We describe metallurgy, the processes by which pure metals are extracted from mineral ores. The chapter ends with a presentation of some properties of transition metals and their biological roles. 

No single volume could contain the complete description of the composition, properties, and structures of ferrous alloys. Further, the effect of heat treatment and other methods of changing the properties of alloys constitutes an entire science unto itself. Accordingly, the description given of ferrous metallurgy will be only an overview of this enormously important area. 

In 1937, dost presented in his book on diffusion and chemical reactions in solids [W. lost (1937)] the first overview and quantitative discussion of solid state reaction kinetics based on the Frenkel-Wagner-Sehottky point defect thermodynamics and linear transport theory. Although metallic systems were included in the discussion, the main body of this monograph was concerned with ionic crystals. There was good reason for this preferential elaboration on kinetic concepts with ionic crystals. Firstly, one can exert, forces on the structure elements of ionic crystals by the application of an electrical field. Secondly, a current of 1 mA over a duration of 1 s (= 1 mC, easy to measure, at that time) corresponds to only 1(K8 moles of transported matter in the form of ions. Seen in retrospect, it is amazing how fast the understanding of diffusion and of chemical reactions in the solid state took place after the fundamental and appropriate concepts were established at about 1930, especially in metallurgy, ceramics, and related areas. 

Jenkins, I. and J.V. Wood Powder Metallurgy An Overview, Ashgate Publishing Company, Brookfield, VT, 1991. 

Ghadiri, M., Farhadpour, F. A., Clift, R. and Seville, J. P. K. (1991). Particle Characterization Size and Morphology. In Powder Metallurgy An Overview. Ed. Jenkins and Wood. London Institute of Metals. 

Tsezos, M. 1985. The selective extraction of metals from solution by microorganisms. A brief overview. Canadian Metallurgy Quarterly, 24 141-4. 

Sethi G, Myers NS, German RM (2008) An overview of dynamic compaction in powder metallurgy. Int Mater Rev 53 219-234... 

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