This chapter begins by presenting a generic eutectic phase diagram and identifying critical points, lines, and features. It then describes the composition and properties of aluminum-silicon and lead-tin eutectic systems, the characteristics of eutectic morphologies, the solidification and scale of eutectic structures, and the competitive growth of dendrites and eutectic colonies or cells. It also examines the different types of precipitation structures that form during slow cooling cycles.

Phase diagrams are graphical representations that show the phases present in the material at various compositions, temperatures, and pressures. This chapter begins with a section describing the construction of phase diagrams for the simple binary isomorphous system. A binary phase diagram can be used to determine three important types of information: the phases that are present, the composition of the phases, and the percentages or fractions of the phases. The chapter then describes the construction of one common type of binary phase diagram i.e., the eutectic alloy system. The major eutectic systems include the aluminum-silicon eutectic system and the lead-tin eutectic system. The chapter discusses the construction of eutectic phase diagrams from free energy curves. It also provides information on peritectic, monotectic, and solid-state reactions in alloy systems. The presence of intermediate phases is also described. Finally, a brief section provides some information on ternary phase diagrams.

This chapter discusses the construction, interpretation, and use of ternary phase diagrams. It begins by examining a hypothetical phase space diagram and several corresponding two-dimensional plots. It then describes one of the most basic tools of metallurgy, the Gibbs triangle, and explains how to construct tie lines to analyze intermediate compositions and phases. It also discusses the use of three-dimensional temperature-composition diagrams, three- and four-phase equilibrium phase diagrams, and binary and ternary phase diagrams associated with the iron-chromium-nickel alloy system.

This chapter presents an overview and survey of solder alloy systems. Extensive reference is made to phase diagrams and their interpretation. The chapter describes the effect of metallic impurities on different solders. The chapter concludes with a review of the key characteristics of eutectic alloys and of the factors most effective at depressing the melting point of solders by eutectic alloying.

Cast irons, like steels, are iron-carbon alloys but with higher carbon levels than steels to take advantage of eutectic solidification in the binary iron-carbon system. Like steel, heat treatment of cast iron includes stress relieving, annealing, normalizing, through hardening, and surface hardening. This chapter introduces solid-state heat treatment of iron castings, covering general considerations for heat treatment and discussing the processes, advantages, and disadvantages of heat treatment of cast iron.

This chapter provides a classification of the types of microstructural changes and transformations and then reviews each type. It presents the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation and explains the thermodynamics of eutectic solidification and eutectoid transformation. An appendix covers growth of eutectoid structure in carburized pearlite.

This chapter introduces many of the key concepts on which metallurgy is based. It begins with an overview of the atomic nature of matter and the forces that link atoms together in crystal lattice structures. It discusses the types of imperfections (or defects) that occur in the crystal structure of metals and their role in mechanical deformation, annealing, precipitation, and diffusion. It describes the concept of solid solutions and the effect of temperature on solubility and phase transformations. The chapter also discusses the formation of solidification structures, the use of equilibrium phase diagrams, the role of enthalpy and Gibb’s free energy in chemical reactions, and a method for determining phase compositions along the solidus and liquidus lines.

Phase diagrams serve as a map to the phases present in an alloy at different temperatures and compositions. They also help in assessing mechanical properties, selecting heat treat temperatures, warning of possible solidification problems, and identifying routes for creating desired microstructures. This chapter familiarizes readers with the information contained in binary phase diagrams and the methods used to extract it. It explains how thermocouple measurements are used to determine liquidus, solidus, and eutectic reaction lines, how differential scanning calorimetry shows where phase reactions occur, and how x-ray diffraction identifies the actual phases present. It demonstrates the use of tie lines for determining phase composition at different temperatures and the application of the level rule to calculate phase fractions. It also discusses the CALPHAD method and presents computed binary phase diagrams that account for the presence of inclusions, oxygen content, and secondary phases.

This chapter is a compilation of beryllium phase diagrams, representing more than 25 binary alloy systems from beryllium-aluminum to beryllium-zirconium. Each diagram is presented along with a summary and source reference.