During fusion welding, the thermal cycles produced by the moving heat source causes physical state changes, metallurgical phase transformations, and transient thermal stresses and metal movement. This chapter begins by discussing weld metal solidification behavior and the solid-state transformations of the main classes of metals and alloys during fusion welding. The main classes include work- or strain-hardened metals and alloys, precipitation-hardened alloys, transformation-hardened steels and cast irons, stainless steels, and solid-solution and dispersion-hardened alloys. The following section provides information on the residual stresses and distortion that remain after welding. The focus then shifts to distortion control of weldments. Inclusions and cracking are discussed in detail. The chapter also discusses the causes for reduced fatigue strength of a component by a weld: stress concentration due to weld shape and joint geometry; stress concentration due to weld imperfections; and residual welding stresses. Inspection and characterization of welds are described in the final section of this chapter.

This chapter discusses different thermal processes applicable to the various alloy groups of stainless steels, namely austenitic, ferritic, martensitic, precipitation hardening, and duplex stainless steels. The processes discussed include soaking, annealing, stress relieving, austenitizing, tempering, aging, and conditioning.

This chapter describes the molecular structures and chemical reactions associated with the production of thermoset and thermoplastic components. It compares and contrasts the mechanical properties of engineering plastics with those of metals, and explains how fillers and reinforcements affect impact and tensile strength, shrinkage, thermal expansion, and thermal conductivity. It examines the relationship between tensile modulus and temperature, provides thermal property data for selected plastics, and discusses the effect of chemical exposure, operating temperature, and residual stress. The chapter also includes a section on the uses of thermoplastic and thermosetting resins and provides information on fabrication processes and fastening and joining methods.

This chapter discusses some of the challenges associated with the analysis of composite structures. It begins with a review of lamina fundamentals and the stress-strain relationships in a single ply under various types of loads. It demonstrates the use of classical lamination theory, discusses the effects of interlaminar free-edge stresses, and explains how to predict the failure of composites using stress and strain criteria as well as the Azzi-Tsai-Hill maximum work theory and the Tsai-Wu failure criterion.

This chapter provides an overview of the fundamental material- and process-related parameters of quenching on residual stress, distortion control, and cracking. It begins with a description of phase transformations during heating and quenching of steel. This is followed by a section on the effects of materials and quench process design on distortion of steel during heat treating. Details on stress raisers and their role in quench cracking are then presented. The chapter ends with various selected case histories of failures attributed to the quenching process.

Ceramics normally have high melting temperatures, excellent chemical stability and, due to the absence of conduction electrons, tend to be good electrical and thermal insulators. They are also inherently hard and brittle, and when loaded in tension, have almost no tolerance for flaws. This chapter describes the applications, properties, and behaviors of some of the more widely used structural ceramics, including alumina, aluminum titanate, silicon carbide, silicon nitride, zirconia, zirconia-toughened alumina (ZTA), magnesia-partially stabilized zirconia (Mg-PSZ), and yttria-tetragonal zirconia polycrystalline (Y-TZP). It also provides information on materials selection, design optimization, and joining methods, and covers every step of the ceramic production process.

This chapter discusses the metallurgy, phase structure, thermal processing, and applications of martensitic stainless steels. The phenomenon of martensite formation is explained. A table listing the compositions of martensitic stainless steels is also presented.

Superalloys tend to operate in environments where they are subjected to high-temperature corrosion, oxidation, and the erosive effects of hot gases. This chapter discusses the nature of these attacks and the effectiveness of various protection methods. It describes the primary forms of oxidation, the development of protective oxides, and the conditions associated with mixed gas corrosion and hot corrosion attack. It discusses oxidation and corrosion testing, the equipment used, and various ways to present the associated data. It describes the effect of gaseous oxidation on different alloys, discusses the formation of oxide scale in the presence of mixed gases, and explains how alloy composition contributes to oxide growth. The chapter discusses the underlying chemistry of hot corrosion, how to identify its effects, and how it progresses under various conditions. It also discusses protective coatings, including aluminide diffusion, overlay, and thermal barrier types, and how they perform in different environments based on their ability to tolerate strain.

This chapter provides a basis for understanding the influence of stainless steel alloy composition and metallurgy on the welding process, which involves complex dynamics associated with melting, refining, and thermal processing. It begins with an overview of the welding characteristics of the categories of stainless steels, namely austenitic, duplex, ferritic, martensitic, and precipitation-hardening stainless steels. This is followed by a discussion of the selection criteria for materials to be welded. Various welding processes used with stainless steel are then described. The chapter ends with a section on some of the practices to ensure safety and weld quality.

The building block of all matter, including metals, is the atom. This chapter initially provides information on atomic bonding and the crystal structure of metals and alloys, followed by a description of three crystal lattice structures of metals: face-centered cubic, hexagonal close-packed, and body-centered cubic. It then describes the four main divisions of crystal defects, namely point defects, line defects, planar defects, and volume defects. The chapter provides information on grain boundaries of metals, processes involved in atomic diffusion, and key properties of a solid solution. It also explains the aspects of a phase diagram that shows what phase or phases are present in the alloy under conditions of thermal equilibrium. Finally, a discussion on the applications of equilibrium phase diagrams is presented.

This chapter discusses the processes used in manufacturing to thermally alter the properties of metals and alloys. It begins with a review of the iron-carbon system, the factors that affect hardenability, and the use of continuous cooling transformation diagrams. It then explains how various steels respond to heat treatments, such as annealing, normalizing, spheroidizing, tempering, and direct and interrupted quenching, and surface-hardening processes, such as flame and induction hardening, carburizing, nitriding, and carbonitriding. It also addresses the issue of temper embrittlement and discusses the effect of precipitation hardening on aluminum and other alloys.

This chapter describes the conditions under which environmental degradation is likely to occur in polymer matrix composites and the potential damage it can cause. It discusses the problems associated with moisture absorption and exposure to solvents, fuels, ultraviolet radiation, lightning strikes, thermal oxidation, and extreme temperatures. It also discusses the factors that influence flammability.

This chapter covers a wide range of finishing and coating operations, including cleaning, honing, polishing and buffing, and lapping. It discusses the use of rust-preventative compounds, conversion coatings, and plating metals as well as weld overlay, thermal spray, and ceramic coatings and various pack cementation and deposition processes. It also discusses the selection and use of industrial paints and paint application methods.

Post-mortem analysis of photovoltaic modules that have degraded performance is essential for improving the long term durability of solar energy. This article focuses on a general procedure for analyzing a failed module. The procedure includes electrical characterization followed by thermal imaging such as forward bias, reverse bias, and lock-in, and emission imaging such as electroluminescence and photoluminescence imaging.

Ceramic-matrix composites possess many of the desirable qualities of monolithic ceramics, but are much tougher because of the reinforcements. This chapter explains how reinforcements are used in ceramic-matrix composites and how they alter energy-dissipating mechanisms and load-carrying behaviors. It compares the stress-strain curves for monolithic ceramics and ceramic-matrix composites, noting improvements afforded by the addition of reinforcements. It then goes on to discuss the key attributes, properties, and applications of discontinuously reinforced ceramic composites, continuous fiber ceramic composites, and carbon-carbon composites. It also describes a number of ceramic-matrix composite processing methods, including cold pressing and sintering, hot pressing, reaction bonding, directed metal oxidation, and liquid, vapor, and polymer infiltration.

This chapter discusses the failure of superalloy components in high-temperature applications where they are subject to the effects of microstructural changes, melting, and corrosion. It explains how overheating can deplete alloying elements and alter the composition and distribution of phases, and how these processes contribute to microstructural changes as a function of time, temperature, and applied stress. It also describes several failure examples and discusses related issues, including damage recovery, refurbishment, and repair.

The decomposition of austenite, during controlled cooling or quenching, produces a wide variety of microstructures in response to such factors as steel composition, temperature of transformation, and cooling rate. This chapter provides a detailed discussion on the isothermal transformation and continuous cooling transformation diagrams that characterize the conditions that produce the various microstructures. It discusses the mechanism and process variables of quenching of steel, explaining the factors involved in the mechanism of quenching. In addition, the chapter provides information on the causes and characteristics of residual stresses, distortion, and quench cracking of steel.

Induction heating, in most applications, is used to selectively heat only a portion of the workpiece that requires treatment. This chapter covers the basic principles, features, and metallurgical aspects of induction heating. The discussion includes the conditions required for induction heating and quenching, the use of magnetic flux concentrators to improve the efficiency of surface heating, and the quenching systems used for induction hardening. The discussion also provides information on time-temperature dependence in induction heating, workpiece distortion in induction surface hardening, residual stresses after induction surface hardening and finish grinding, and input and output control of steel for induction surface hardening of gears.

This chapter provides an overview of the tools and techniques, as well as some of the underlying theory, that have proven useful for process modeling and simulation. It begins by presenting the framework of a thermoset cure model that accounts for kinetics, viscosity, heat transfer, flow, voids, and residual stress. It then discusses each variable in detail, explaining how it affects the cure process, how it is measured, and how it can be expressed mathematically in the form of a simple model. The discussions throughout the chapter are supported by numerous images, diagrams, and data plots.

This chapter provides information on various contributors to failure of carburized and carbonitrided components, with the primary focus on carburized components. The most common contributors covered include component design, selection of proper hardenability, increased residual stress, dimensional stability, and generation of quenching and grinding cracks. They also include insufficient case hardness and improper core hardness, influence of surface carbon content and grain size, internal oxidation, structure of carbides, and inclusion of noncarbide. Details on micropitting, macropitting, case crushing, pitting corrosion, and partial melting are also provided.