Many metallic components, such as retorts in heat treat furnaces, furnace heater tubes and coils in chemical and petrochemical plants, waterwalls and reheater tubes in boilers, and combustors and transition ducts in gas turbines, are subject to oxidation. This chapter explains how oxidation affects a wide range of engineering alloys from carbon and Cr-Mo steels to superalloys. It discusses the kinetics and thermodynamics involved in the formation of oxides and the effect of surface and bulk chemistry. It provides oxidation data for numerous alloys and intermetallics in terms of weight gain, metal loss, depth of attack, and oxidation rate. It also discusses the effect of metallurgical and environmental factors such as oxygen concentration, high-velocity combustion gas streams, chromium depletion and breakaway, component thickness, and water vapor.

This chapter provides a brief review of industry’s battle with fatigue and fracture and what has been learned about the underlying failure mechanisms and their effect on product lifetime and service. It recounts some of the tragic events that led to the discovery of fatigue and brittle fracture and explains how they reshaped design philosophies, procedures, and tools. It also discusses the influence of material and manufacturing defects, operating conditions, stress concentration and intensity, temperature and pressure, and cyclic loading, all of which play a role in the onset of fatigue cracking and thus should be considered when predicting useful product life.

This chapter examines boiler tube failures attributed to operation-related causes. It discusses failures due to rapid start-ups, excessive load swing, excessive heat inputs, poor water chemistry control, and water-treatment methods.

This chapter describes the corrosion behavior of beryllium in gaseous atmospheres, including oxygen, nitrogen, carbon dioxide, and carbon monoxide. It also discusses the development of high-temperature corrosion-resistant beryllium alloys.

The refractory metals include niobium, tantalum, molybdenum, tungsten, and rhenium. These metals are considered refractory because of their high melting points, high-temperature mechanical stability, and resistance to softening at elevated temperatures. This article discusses the composition, properties, fabrication procedures, advantages and disadvantages, and applications of these refractory metals and their alloys. A comparison of some of the properties of the refractory metals with those of iron, copper, and aluminum is given in a table. The article concludes with a brief section on refractory metal protective coatings.

This chapter discusses the compositions, mechanical properties, phase structure, stabilization, corrosion resistance, and advantages of austenitic stainless steels. Austenitic alloys are classified and reviewed in three groups: (1) lean alloys, such as 201 and 301, which are generally used when high strength or high formability is the main objective; (2) chromium nickel alloys used for high temperature oxidation resistance; and (3) chromium, molybdenum, nickel, and nitrogen alloys used for applications where corrosion resistance is the main objective.

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.

Stainless steel retains strength and has excellent oxidation resistance from room temperature to nearly 1000 deg C relative to competitive materials. This chapter focuses on the high-temperature oxidation of stainless steel by oxygen or water vapor. It begins by discussing the thermodynamic conditions and electrochemical nature of oxidation and providing information on transient oxidation. This is followed by a description of Wagner's theory for metal oxidation. The volatile nature of Cr 2 O 3 is then reviewed. The chapter further discusses the causes and preventive measures of spalling and cracking of oxide scale. It ends with a section providing information on oxidation behaviors under less-oxidizing atmospheres.

Durability is a generic term used to describe the performance of a material or a component made from that material in a given application. In order to be durable, a material must resist failure by wear, corrosion, fracture, fatigue, deformation, and exposure to a range of service temperatures. This chapter covers several types of component and material failure associated with wear, temperature effects, and crack growth. It examines temperature-induced, brittle, ductile, and fatigue failures as well as failures due to abrasive, erosive, adhesive, and fretting wear and cavitation fatigue. It also discusses preventative measures.

This chapter discusses the ambient-temperature corrosion characteristics of aluminum metal-matrix composites (MMCs), including composites formed with boron, graphite, silicon carbide, aluminum oxide, and mica. It also discusses the effect of stress-corrosion cracking on graphite-aluminum composites and the use of protective coatings and design criteria for corrosion prevention.

This chapter focuses on various factors to be considered at design stage to minimize corrosion. It begins by providing information on design considerations and general corrosion awareness. This is followed by a description of several factors influencing materials-component failure. Details on design and materials selection, which assist in controlling corrosion, are then provided. The chapter ends with a discussion on the design factors that influence corrosion.

A brittle fracture occurs at stresses below the material's yield strength (i.e., in the elastic range of the stress-strain diagram). This chapter focuses on brittle fracture in metals and, more specifically, ferrous alloys. It lists the factors that must all be present simultaneously in order to cause brittle fracture in a normally ductile steel. The chapter then discusses the macroscale characteristics and microstructural aspects of brittle fracture. A summary of the types of embrittlement experienced by ferrous alloys is presented. The chapter concludes with a brief section providing information on mixed fracture morphology.

This chapter describes cast steel features that may be identified or attributed to component failure during heat treatment or subsequent processing or service, namely porosity (generated by the presence of gas as well as by shrinkage pores), decarburization, cold joint, and inclusions.

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.

The ability to accurately assess the remaining life of components is essential to the operation of plants and equipment, particularly those in service beyond their design life. This, in turn, requires a knowledge of material failure modes and a proficiency for predicting the near and long term effects of mechanical, chemical, and thermal stressors. This chapter presents a broad overview of the types of damage to which materials are exposed at high temperatures and the approaches used to estimate remaining service life. It explains how operating conditions in power plants and oil refineries can cause material-related problems such as embrittlement, creep, thermal fatigue, hot corrosion, and oxidation. It also discusses the factors and considerations involved in determining design life, defining failure criteria, and implementing remaining-life-assessment procedures.

Optoelectronic components can be readily classified as active light-emitting components (such as semiconductor lasers and light emitting diodes), electrically active but non-emitting components, and inactive components. This chapter focuses on the first category, and particularly on semiconductor lasers. The discussion begins with the basics of semiconductor lasers and the material science behind some causes of device failure. It then covers some of the common failure mechanisms, highlighting the need to identify failures as wearout or maverick failures. The chapter also covers the capabilities of many key optoelectronic failure analysis tools. The final section describes the common steps that should be followed so as to assure product reliability of optoelectronic components.

This chapter concentrates on the better-known and widely studied phenomenon of pitting corrosion of passive metals. The discussion focuses on different parameters that influence pitting corrosion, namely environment, metal composition, potential, temperature, surface condition, and inhibitors. It also provides information on various stages of pitting: passive film breakdown, metastable pitting, pit growth, and pit stifling or death.

Gears can fail in many different ways, and except for an increase in noise level and vibration, there is often no indication of difficulty until total failure occurs. This chapter begins with the classification of gear failure modes, followed by sections discussing the characteristics of various fatigue failures. Then, it provides information on the modes of impact fractures, wear, scuffing, and stress rupture. Next, the chapter describes the causes of gear failures and discusses the processes involved in conducting the failure analysis. Finally, the chapter presents examples of gear failure analysis.

Elevated-temperature failures are the most complex type of failure because all of the modes of failures can occur at elevated temperatures (with the obvious exception of low-temperature brittle fracture). Elevated-temperature problems are real concerns in industrial applications. The principal types of elevated-temperature failure mechanisms discussed in this chapter are creep, stress rupture, overheating failure, elevated-temperature fatigue, thermal fatigue, metallurgical instabilities, and environmentally induced failure. The causes, features, and effects of these failures are discussed. The cooling techniques for preventing elevated-temperature failures are also covered.

This chapter explains how the authors assessed the potential risks of creep-fatigue in several aerospace applications using the tools and techniques presented in earlier chapters. It begins by identifying the fatigue regimes encountered in the main engines of the Space Shuttle. It then describes the types of damage observed in engine components and the methods used to mitigate problems. It also discusses the results of analyses that led to changes in design or approach and examines fatigue-related issues in turbine engines used in commercial aircraft.