Synthesis, Properties and Applications of Intermetallic Phases

Abstract

Intermetallic phases constitute a unique class of materials composed of two or more metals, sometimes non-metallic elements also, in definite proportions. They have well-defined stoichiometry, crystal structure and can exhibit metallic, covalent or ionic bonding. High mechanical strength, resistance to corrosion and adequate ductility of intermetallic phases make them widely applicable as structural materials for automobiles, aerospace, telecommunication, electronics, transport and heavy industries. There is a huge demand for alloys having high mechanical strength and corrosion resistance at elevated temperatures for energy applications. The physical properties and mechanical strength of alloys are governed by the presence of intermetallic phases in these alloys. The formation of these phases in a given alloy system on other hands is governed by the nature of synthesis of alloys, level of impurity phases present and the heat treatment process. Experimental conditions, like, level of vacuum, annealing temperature, rate of cooling and thermal shock are among the factors that play vital role in tailoring their properties. In the present chapter, types of intermetallic phases, various experimental procedures for their synthesis, processing and their properties will be discussed. Details of synthesis processes including heat treatment in different types of furnaces, mechanical alloying, electrochemical processes, chemical reduction methods will be discussed. Influence of annealing conditions on material properties will also be presented. The knowledge of phase diagram, structure and thermodynamic parameters in fixing the material properties will be brought out. The chapter will also include some of the technologically important intermetallic phases, their method of synthesis, properties and applications.