Fiber-reinforced metal-matrix composites have carved out a niche in applications requiring high strength to weight ratios, but they are susceptible to failure when exposed to high temperatures and cyclic loads. This chapter discusses the obstacles that must be overcome to improve the creep-fatigue behavior of these otherwise promising materials. It addresses six areas that have been the focus of intense research, including thermal-expansion and elastic-viscoplastic mismatch, thermally induced biaxiality and interply stresses, creep and cyclic relaxation of residual stresses, and enhanced interfaces for oxidation.

The solidification process has a major influence on the microstructure and mechanical properties of metal casting as well as wrought products. This appendix covers the fundamentals of solidification. It discusses the formation of solidification structures, the characteristics of planar, cellular, and dendritic growth, the basic freezing sequence for an alloy casting, and the variations in cooling rate, heat flow, and grain morphology in different areas of the mold. It also describes the types of segregation that occur during freezing, the effect of solidification rate on secondary dendrite arm spacing, and the factors that contribute to porosity and shrinkage.

This chapter provides an overview of beryllium casting practices and the challenges involved. It discusses the stages of solidification, the effect of cooling rate, the difficulty of heat removal, and the potential for hot cracking. It describes common melting techniques, including vacuum induction melting, vacuum arc melting, and electron beam melting, and some of the ways they have been used to cast beryllium alloys. The chapter also includes information on metal purification and grain refinement procedures.

It is well established that solidification behavior in the fusion zone controls the size and shape of grains, the extent of segregation, and the distribution of inclusions and defects such as porosity and hot cracks. Since the properties and integrity of the weld metal depend on the solidification behavior and the resulting microstructural characteristics, understanding weld pool solidification behavior is essential. This article provides a general introduction of key welding variables including solidification of the weld metal or fusion zone and microstructure of the weld and heat-affected zone. It discusses the effects of welding on microstructure and the causes and remedies of common welding flaws.

Almost all metals and alloys are produced from liquids by solidification. For both castings and wrought products, the solidification process has a major influence on both the microstructure and mechanical properties of the final product. This chapter discusses the three zones that a metal cast into a mold can have: a chill zone, a zone containing columnar grains, and a center-equiaxed grain zone. Since the way in which alloys partition on freezing, it follows that all castings are segregated to different categories. The different types of segregation discussed include normal, gravity, micro, and inverse. The chapter also provides information on grain refinement and secondary dendrite arm spacing and porosity and shrinkage in castings. It concludes with a brief overview of six of the most important casting processes in industries: sand casting, plaster mold casting, evaporative pattern casting, investment casting, permanent mold casting, and die casting.

A systematic procedure for minimizing risks involved in heat treated steel components requires a combination of metallurgical failure analysis and fitness for service with respect to safety and reliability based on risk analysis. This chapter begins with an overview of heat treat processing of steels. This is followed by sections on various aspects of heat treatment design and heat treating practices for minimizing distortion. Influence of design, steel grade, and condition is then illustrated in the examples of failures due to heat treatment. A procedure is analyzed to improve the performance of the design process of a component. A heat-transfer model, coupling with a phase transformation model, a thermomechanical model, and a thermochemical model, is also considered. The chapter further provides information on the failure aspects of and heat treatment procedures applied to welded components. It ends with a section on risk-based approach applicable to heat treated steel components.

This article reviews the basic physics behind active photon injection for local photocurrent generation in silicon and thermal laser stimulation along with standard scanning optical microscopy failure analysis tools. The discussion includes several models for understanding the local thermal effects on metallic lines, junctions, and complete devices. The article also provides a description and case study examples of multiple photocurrent and thermal injection techniques. The photocurrent examples are based on Optical Beam-Induced Current and Light-Induced Voltage Alteration. The thermal stimulus examples are Optical Beam-Induced Resistance Change/Thermally-Induced Voltage Alteration and Seebeck Effect Imaging. Lastly, the article discusses the application of solid immersion lenses to improve spatial resolution.

This chapter discusses the various factors pertinent to gravity permanent mold (GPM) castings, along with their advantages, limitations, and significance. The discussion covers the geometric factors, process and manufacturing elements, gating practices, and feeding principles of and pouring systems in GPM. The influences of mold coatings on GPM and low pressure permanent mold castings are described. The chapter also discusses various processes involved in the engineering of core boxes and cooling of GPM for casting integrity and cycle time control. It provides information on some of the processes involved in post-casting operations, namely de-coring and de-gating. The key design aspects for consideration in water quenching during the T6 heat treatment are reviewed. The chapter also provides information on two critical cycle events important in engineering at the manufacturing facility: tipper cycle planning and table or cell cycle planning.

Steel is broadly classified as plain-carbon steels, low-alloy steels, and high-alloy steels. This chapter begins by describing microconstituents of low- and medium-carbon steel, including bainite and martensite. This is followed by a section discussing the effect of alloying elements on steel. Then, it provides an overview of steel casting applications. Next, the chapter reviews engineering guidelines for steel castings and feeder design. The following section provides information on feeding aids. Further, the chapter describes the elements of gating systems for steel castings. It also describes the alloys, properties, applications, and engineering details of steel. Finally, the chapter explains defects in steel castings and presents guidelines for problem solving with examples.

This chapter discusses the thermally induced changes that occur on the surface of steel exposed to different environments. It explains how oxide scales form during heat treating and how factors such as temperature, composition, and surface finish affect growth rates, grain structure, and uniformity. It provides examples of oxides that form beneath the surface of steel and explains why it occurs. It describes the conditions associated with decarburization and explains how to determine the depth of decarburized layers in eutectoid, hypoeutectoid, and hypereutectoid steels. It also discusses the carburizing process, the factors that determine the depth and gradient of the carburized case, the effect of post-process treatments, and a variation on the process known as ferritic carbonitriding.

This chapter explains various aspects of the foundry process that the design engineer should consider when designing steel castings. It discusses special feeding aids, such as tapers, padding, ribs, and chills that may be used by foundry personnel to promote directional solidification. The chapter addresses the design of castings to reduce the occurrence of internal shrinkage. It provides a detailed discussion on design considerations for molding, cleaning, machining, and function.