This chapter addresses the basic concepts important to understanding corrosion of metals. It begins with an overview of the three types of behaviors that a metal exhibits when immersed in an environment and of the four requirements of a corrosion cell. The chapter then covers the important characteristics of metals with respect to corrosion, namely the metallurgical characteristics, the inherent tendency to corrode, and the tendency to form insoluble corrosion products. The important characteristics of aqueous solutions with respect to corrosion are then addressed. The characteristics include: conductivity of the solution, acidity and alkalinity, oxidizing power, degree of ionization, and solubility in the solution. These characteristics, in combination with the characteristics of the metal, will determine the corrosion behavior of a metal/environment combination. The chapter concludes with a section on the determination of corrosion rates and corrosion rate allowances.

This chapter introduces the principal heat treating processes, namely normalizing, annealing, stress relieving, surface hardening, quenching, and tempering. An overview of four of the more popular surface hardening treatments, namely carburizing, carbonitriding, nitriding, and nitrocarburizing, is provided.

This chapter provides a short introduction to phase transformations, namely, the liquid-to-solid phase transformations that occur during solidification and the solid-to-solid transformations that are important in processing, such as heat treatment. It also introduces the concept of free energy that governs whether or not a phase transformation is possible, and then the kinetic considerations that determine the rate at which transformations take place. The chapter also describes important solid-state transformations such as spinodal decomposition and martensitic transformation.

The mechanical behavior of a material is its response to an applied load or force. Important mechanical properties are strength, hardness, stiffness, and ductility. This chapter discusses three principal ways in which these properties are tested: tension, compression, and shear. Important tensile properties that can be determined by the tensile test include yield strength, ultimate tensile strength, ductility, resilience, and toughness. The chapter describes the effects of stress concentrations on ductile metals under cyclic loads. Other topics covered include combined stresses, yield criteria, and residual stresses of metals.

Statistics, data analysis, root cause analysis, and problem-solving processes play a key role in failure investigations. This chapter explains how to collect failure investigation data, how to build and maintain a database for company-related failures, and how to use corresponding statistics including type of failure, material, and root cause. It describes the purpose and benefits of conducting a root cause analysis and the factors, namely relative failure importance and company value, that determine when an investigation should be performed. The chapter also discusses the four-step problem-solving process as it applies to failure investigation, how to assemble an investigation team, and the details of organization and planning. It concludes with a case history of the Firestone 500 steel-belted tire failure, stressing the importance of a systematic approach to failure investigations.

Ion nitriding equipment can be categorized into two groups: cold-wall continuous direct current (dc) equipment and hot-wall pulsed dc equipment. This chapter focuses on these two categories along with other important considerations for ion (plasma) nitriding equipment and processing. Other important considerations discussed include the hollow cathode effect, sputter cleaning, furnace loading, pressure/voltage relationships, workpiece masking, and furnace configuration options. The chapter describes five methods of cooling parts from the process temperature to an acceptable exposure temperature after plasma nitriding. The chapter also presents some of the advantages of the pulsed plasma process.

This introductory article describes the various aspects of chemical structure and composition that are important to an understanding of polymer properties and their eventual effect on the end-use performance of engineering plastics, namely thermoplastics and thermosets. The most important properties of polymers and the most significant influences of structure on those properties are covered. The article also includes some general information on the classification and naming of polymers and plastics.

This chapter discusses the important role of metallography and the metallographer in predicting and understanding the properties of metals and alloys. Examples are presented of a metallographer working as part of a team in a research laboratory of a large steel company and a metallographer working alone at a small iron foundry. The three basic areas in all metallography laboratories are discussed: the specimen preparation area, the polishing/etching area, and the observation/micrography area. Important safety issues in a metallographic laboratory are also considered.

This chapter familiarizes readers with the methods used to quantify the effects of fatigue on component lifetime and failure. It discusses the development and use of S-N (stress amplitude vs. cycles to failure) curves, the emergence of strain-based approaches to fatigue analysis, and important refinements and modifications. It demonstrates the use of approximate equations, including the method of universal slopes and the four-point correlation technique, which provides reasonable estimates of elastic and plastic lines from information obtained in standard tensile tests. It also discusses high-cycle, low-cycle, and ultra-high cycle fatigue and presents several models that are useful for fatigue life predictions.

This chapter discusses the concept of mean stress and explains how it is used in fatigue analysis and design. It begins by examining the stress-strain response of test samples subjected to cyclic forces and strains, noting important features and what they reveal about materials and their fatigue behaviors. It then discusses the challenge of developing hysteresis loops for complex loading patterns and accounting for effects such as ratcheting and stress relaxation. The sections that follow provide a summary of the various ways mean stress is described in the literature and the methods used to calculate or predict its effect on the fatigue life of machine components. The discussion also sheds light on why tensile mean stress is detrimental to both fatigue life and ductility, while compressive mean stress is highly beneficial.

This chapter reviews the theories that have emerged from the widespread study of multiaxial fatigue and assesses their validity using data from different sources. It begins by providing background on the studies that the chapter draws on, pointing out differences in methodology and explaining how they influence test results and data. It then discusses the concept of critical planes and how they are used to correlate the effects of uniaxial loading with multiaxial fatigue behaviors. The section that follows covers the various methods used to analyze multiaxial fatigue and identifies one that best treats the general case. The chapter also defines two important factors, the triaxiality factor and the multiaxiality factor, and presents the results of an extensive study to determine how the two factors are related. One of the more interesting findings is that the atomic structure of a material has a significant effect on which theory best describes its fatigue behavior.

This chapter is largely a compendium of best practices and procedures for minimizing the effects of fatigue. It explains how to make products more resistant to fatigue by choosing the right materials and manufacturing processes, avoiding geometries and features that concentrate strains, preventing or removing surface damage, and by inducing compressive mean stresses that prolong fatigue life. It also discusses the use of property conditioning and restoration treatments, the benefits of interference fits and processes such as coaxing, the effects of assembly damage and operating overload, the importance of surface cleanliness and finish, and the role of inspection, testing, replacement, and repair in safe-life and fail-safe designs. Examples highlighting the benefits and potential pitfalls of proof loading tests are included as well.

This chapter discusses the effect of fatigue on polymers, ceramics, composites, and bone. It begins with a general comparison of polymers and metals, noting important differences in microstructure and cyclic loading response. It then presents the results of several studies that shed light on the fatigue behavior and crack growth mechanisms of common structural polymers and moves on from there to discuss the fatigue behavior of bone and how it compares to stable and cyclically softening metals. It also discusses the fatigue characteristics of engineered and composited ceramics and ceramic fiber-reinforced metal-matrix composites.

This appendix provides supplemental information on the metallurgical aspects of atomic structure, the use of dislocation theory, heat treatment processes and procedures, important engineering materials and strengthening mechanisms, and the nature of elastic, plastic, and creep strain components. It also provides information on mechanical property and fatigue testing, the use of hysteresis energy to analyze fatigue, a procedure for inverting equations to solve for dependent variables, and a method for dealing with the statistical nature of failure.

Alloying, heat treating, and work hardening are widely used to control material properties, and though they take different approaches, they all focus on imperfections of one type or other. This chapter provides readers with essential background on these material imperfections and their relevance in design and manufacturing. It begins with a review of compositional impurities, the physical arrangement of atoms in solid solution, and the factors that determine maximum solubility. It then describes different types of structural imperfections, including point, line, and planar defects, and how they respond to applied stresses and strains. The chapter makes extensive use of graphics to illustrate crystal lattice structures and related concepts such as vacancies and interstitial sites, ion migration, volume expansion, antisite defects, edge and screw dislocations, slip planes, twinning planes, and dislocation passage through precipitates. It also points out important structure-property correlations.

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.

Structurally differentiated intermetallic phases are important constituents in the microstructure of aluminum alloys, with the potential to influence properties, behaviors, and processing characteristics. These phases can form in aluminum-silicon alloys with transition metals (Fe, Mn, Ni, Cr, V, Ti) and with metals such as Mg and Cu. This chapter is a compilation of phase diagrams, microstructure images, and tables, providing information on more than 30 binary, ternary, and quaternary alloy systems associated with intermetallic phases in aluminum-silicon castings. Each section includes tabular information and data on the intermetallic phases in the aluminum corner of the equilibrium phase diagram, the characteristics of the crystal lattice of intermetallic p