Tribology plays a critical role in extrusion. This chapter provides an overview of tribology in extrusions including a discussion about the friction models at various locations of the extrusion tooling/die material interfaces and a discussion about wear and lubrication in extrusion die and tooling. The chapter shows a flow diagram highlighting the significant input variables necessary for computer simulation using the fundamentals of friction and thermodynamics models. The chapter explains the influence of principal variables on temperature rise in extrusion. It describes the most common industrial methods of isothermal extrusion of aluminum alloys.

This chapter provides an overview of sintering techniques and the microstructures and properties that can be achieved in different material systems. It covers conventional furnace sintering, microwave and laser sintering, hot and hot-isostatic pressing, and spark plasma sintering. It describes the advantages and disadvantages of each method, the mechanisms involved, and the effect of sintering parameters on the density, grain size, and mechanical properties of titanium and tungsten heavy alloys, stainless steel, cemented carbides, ceramics, composites, and rare earth magnets.

This chapter describes how forces and temperatures generated during sintering influence particle bonding, grain growth, shrinkage, and densification as well as bulk material properties. It explains how density, a good predictor of mechanical and electrical properties, can be controlled by proper selection of sintering time, temperature, and particle size for various steels, ceramics, and tungsten and titanium alloys.

This chapter examines the microstructure of metallic components produced by casting and compares them with microstructures achieved by means of powder metallurgy. It shows how metals and alloys obtained by various processing routes differ in terms of grain size, secondary phases, oxide and carbide dispersions, porosity, dendritic formation, and properties such as hardness, toughness, tensile strength, and yield strength.

The porous structure of powder-metal materials, and thus the sintering method, has a significant impact not only on the properties of PM components, but also on how they respond to surface treatments and fabrication processes such as coating and joining. This chapter explains how the microstructure of PM parts achieved by different sintering methods influences the development of galvanized coatings and the mechanisms involved in sinter bonding and various welding and brazing processes. It presents and interprets the results of several studies in which PM materials, including iron, copper, stainless steel, brass, and bronze alloys, are joined by spot welding, projection welding, and solid-state welding as well as furnace and microwave brazing. It also examines the effects of ZrSiO 4 additions on the friction and wear behaviors of PM bronze brake-lining materials.

This chapter reviews some of the differences between powder metallurgy and additive manufacturing and explains how they influence the microstructure and properties of various alloys and the formation of defects in manufactured parts.

The appendix contains detailed simulation examples through which readers learn how to format and analyze problems using the LAMMPS molecular dynamics simulator. By means of simulation, readers will determine the thermal expansion coefficient of copper, generate stress-strain plots for aluminum at different temperatures, calculate the surface energy of copper for different crystal orientations, investigate diffusion effects in BCC iron, estimate the sliding friction between graphene layers, compare the stacking fault energy of silver and aluminum, and analyze the properties and behaviors of liquids and gases. All examples employ a systematic problem-solving approach and include necessary input code.

This chapter describes the processes and alloys used in the casting of aluminum components, the advantages and disadvantages of the different shape-casting methods, and the major factors that influence alloy selection for shape-casting applications. An overview of the heat treatment of cast products is also included.

This chapter presents the theory and practice associated with the application of thin films. The first half of the chapter describes physical deposition processes in which functional coatings are deposited on component surfaces using mechanical, electromechanical, or thermodynamic techniques. Physical vapor deposition (PVD) techniques include sputtering, e-beam evaporation, arc-PVD, and ion plating and are best suited for elements and compounds with moderate melting points or when a high-purity film is required. The remainder of the chapter covers chemical vapor deposition (CVD) processes, including atomic layer deposition, plasma-enhanced and plasma-assisted CVD, and various forms of vapor-phase epitaxy, which are commonly used for compound films or when deposit purity is less critical. A brief application overview is also presented.

This appendix provides a brief review of thin film deposition methods and their uses in a question and answer format. The questions deal with recommended practices, process conditions, terminology, and classifications.

A working knowledge of diffusion is necessary to understand and predict the behavior of metals and alloys during manufacturing and in certain types of service. This chapter covers the fundamentals of diffusion in solids and some of the applications in which diffusion plays a role. It discusses the mechanisms behind interstitial, substitutional, grain boundary, and surface diffusion, the derivation and use of Fick’s laws, and the basic principles of diffusion coating processes, including carburizing, nitriding, nitrocarburizing, cyaniding, carbonitriding, boriding, aluminizing, siliconizing, chromizing, vanadizing, and titanizing. It also discusses diffusion bonding and presents several approaches for dealing with oxide barrier problems.

This chapter familiarizes readers with the use of Fick’s laws of diffusion in heat treating, coating, and other metallurgical processes. It contains worked solutions to nearly 30 problems requiring the calculation of activation energy, diffusion coefficient, concentration level, surface layer thickness, case depth, and processing time and temperature. The selected problems deal with various types of iron, steel, and nonferrous alloys and processes ranging from aluminizing, chromizing, carburizing, and plasma nitriding to hydrogen dissipation, decarburizing, and oxidation. A few diffusion problems involving single-crystal silicon are also included.

This chapter provides readers with worked solutions to more than 25 problems related to compositional impurities and structural defects. The problems deal with important issues and challenges such as the design of low-density steels, the causes and effects of distortion in different crystal structures, the ability to predict the movement of dislocations, the influence of impurities on defects, the relationship between gain size and material properties, the identification of specific types of defects, the selection of compatible metals for vacuum environments, and the effect of twinning planes on stacking sequences. The chapter also includes problems on how the formation of precipitates can produce slip planes and how grain boundaries can act as obstacles to dislocation motion.

The existence of austenite and ferrite, along with carbon alloying, is fundamental in the heat treatment of steel. In view of the importance of structure and its formation to heat treatment, this chapter describes the various microstructures that form in steels, the various factors that determine the formation of microstructures during heat treatment processing of steel, and some of the characteristic properties of each of the microstructures. The discussion also covers the constitution of iron during heat treatment and the phases of heat-treated steel with elaborated information on iron phase transformation, hysteresis in heating and cooling, ferrite and austenite as two crystal structures of solid iron, and the diffusion coefficient of carbon.