Grain size has a determining effect on the mechanical properties of steel and responds favorably to forging and heat treating. This chapter explains how to measure and quantify grain size and how to control it through thermal cycling and forging operations. It describes how surface tension acting on grain-boundary segments contributes to grain growth and how the formation of new grains, driven by phase transformations and recrystallization, lead to a reduction in average grain size. It also discusses the effect of alloying elements on grain growth rates, particularly the curbing effect of particle and solute drag.

Bainite is an intermediate temperature transformation product of austenite. This chapter describes the conditions under which bainite is likely to form. It discusses the effects of alloying on bainitic transformation, the difference between upper and lower bainite, and the influence of solute drag on bainite formation mechanisms. It also discusses the development of ferrite-carbide bainites and their effect on toughness, hardness, and ductility.

This chapter discusses the causes and effects of wear along with prevention methods. It covers abrasive, erosive, erosion-corrosion, grinding, gouging, adhesive, and fretting wear. It also discusses various forms of contact-stress fatigue, including subsurface-origin fatigue, surface-origin fatigue, subcase-origin fatigue (spalling fatigue), and cavitation fatigue.

The modeling and simulation activities in the field of high-pressure cold spray can be divided into two main parts: solid mechanics and fluid dynamics. This chapter focuses on these parts of modeling work in cold spray research. The discussion covers the objective, principal concepts, methods, and outcome of modeling and simulation of particle impact and of in-flight history of particles in cold spraying. The concept of integration of particle impact and fluid flow modeling to optimize cold spray deposition for a given material is also explained.

The wear caused by contact stress fatigue is the result of a wide variety of mechanical forces and environments. This chapter discusses the characteristics of four types of contact stress fatigue on mating metal surfaces: surface, subsurface, subcase, and cavitation. Features and corrective actions for these contact stress fatigue are discussed. The chapter also lists some possible ways to reduce the cavitation fatigue problem.

This chapter covers the practices and procedures used for shape casting metals and alloys. It begins with a review of the factors that influence solidification and contribute to the formation of casting defects. It then describes basic melting methods, including induction, cupola, crucible, and vacuum melting, and common casting techniques such as sand casting, plaster and shell casting, evaporative pattern casting, investment casting, permanent mold casting, cold and hot chamber die casting, squeeze casting, semisolid metal processing, and centrifugal casting.

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.

This chapter discusses the extrusion characteristics of relatively soft aluminum alloys. It begins by identifying alloy designations within the class and the types of extrusions made from them. It then explains how extruded shapes and cross-sections are defined and how to analyze and assess important process variables such as runout, extrusion pressure, ram speed, and butt thickness. It also provides best practices for various operations and explains how to identify and remedy common extrusion defects.

This chapter is a detailed account of various attributes related to mixing and testing of powder-binder feedstocks. Mixing parameters and their effects on feedstock properties is discussed. The attributes reviewed include mixture homogeneity, wetting, powder-binder ratio, feedstock density, elastic modulus, rheological behavior, particle size, formulation control, feedstock mixing, and feedstock properties. The chapter also provides information on the processes involved in feedstock preparation and testing.

This appendix discusses the sizing, scaling, and configuration requirements of the basic components in a quench cooling system, including tanks, pumps, hoses, and inlet and outlet fixtures and the materials from which they are made.

This chapter discusses the characteristics of eutectoid transformations, a type of solid-state transformation associated with invariant reactions, focusing on the iron-carbon system of steel. It describes the compositions, characteristics, and properties of ferrite, eutectoid, hypoeutectoid, and hypereutectoid structures and how they are affected by the addition of various alloying elements. The chapter also discusses the formation of peritectoid structures in the uranium-silicon alloy system.

This chapter reviews the types of friction that are of concern in tribological systems along with their associated causes and effects. It discusses some of the early discoveries that led to the development of friction laws and the understanding that friction is a system effect that can be analyzed based on energy dissipation. It describes the stick-slip behavior observed in wiper blades, the concept of asperities, and the significance of the shape, lay, roughness, and waviness of surfaces in sliding contact. It explains how friction forces are measured and how they are influenced by speed, load, and operating environment. It also covers rolling contact and fluid friction and the effect of lubrication.

Leaks can occur as the result of several failure causes. This chapter reviews the causes, features, and impact of various types of leaks, namely gasket leaks, O-ring leaks, bond-joint leaks, weld leaks, polyvinyl chloride leaks, valve leaks, and structural leaks.

This chapter examines two important strengthening mechanisms, martensitic and bainitic transformations, both of which occur under nonequilibrium cooling conditions. It explains how time-temperature-transformation diagrams are constructed and how they are used to understand and control the formation of martensite and bainite in steel and other alloys. It describes the morphology of both types of structures, the factors that influence their formation, how they respond to tempering processes, and their effect on mechanical properties and behaviors. It also discusses the role of transformation hysteresis in shape memory alloys.

This chapter discusses the advantages, limitations, and applications of various aluminum casting processes, namely green sand casting process, air set or no-bake molding process, vacuum molding process, evaporative foam casting process, and die casting process. The processes covered also include gravity permanent molding, low-pressure permanent molding, counter pressure, squeeze casting, investment casting, rapid prototype casting, cast forge hybrid, and semisolid metal processes.

This chapter is a detailed account of various factors pertinent to the development and launch of a product. It begins by describing the five phases in the product launch process, namely product design and development, process design and development, product and process validation, product launch, and continuous improvement. This is followed by sections covering product-process flow diagrams and also the process elements considered for process failure mode and effects analysis. Some of the aspects covered by the engineering specifications to meet the product performance requirements are then reviewed. Details on product validation requirements and definitions of parameters related to the launch process are also provided. The chapter discusses the purpose of manufacturing control plan, along with an illustration of a manufacturing control plan outlined for a safety-critical suspension casting. It ends with an overview of the contents of a program launch manual.

This chapter describes the processes involved in alloy production, including melting, casting, solidification, and fabrication. It discusses the effects of alloying on solidification, the formation of solidification structures, supercooling, nucleation, and grain growth. It describes the design and operation of melting furnaces as well as melting practices and the role of fluxing. It also discusses casting methods, nonferrous casting alloys, and atomization processes used to make metal powders.

Most quenched steels are tempered because the toughness of as-quenched steels is generally very poor. The tempering operation sacrifices strength for improvements in ductility and toughness. This chapter discusses the tempering process, the challenge of tempered martensite embrittlement, and the effect of wt% carbon on toughness. It also explains how alloying elements improve the hardenability and tempering response of plain carbon steels.

This chapter discusses five forms of mechanically assisted degradation of metals: erosion, fretting, fretting fatigue, cavitation and water drop impingement, and corrosion fatigue. Emphasis is placed on the mechanisms and the factors affecting these forms of degradation.