Many scientific-technological advances depend critically on solid-state elastic properties, their magnitudes, and their responses to variables like stress and temperature. This chapter provides the definitions and descriptions of elastic constants and emphasizes five aspects of engineering-material solid-state elastic constants: general properties; interrelationships; relationships, especially thermodynamic to other physical properties; changes during cooling from ambient to near-zero temperature; and near-zero-temperature behavior.

This chapter, presented in a question-and-answer format, covers many practical aspects of high-entropy alloys (HEAs). It provides clear and concise answers to more than 50 questions, imparting knowledge on alloying elements, heat treatments, diffusion mechanisms, phase formation, lattice distortion, crystal and grain structures, structure-property relationships, microstructure control, and characterization methods. It likewise explains how to calculate the effect of strengthening processes on the mechanical properties of HEAs and offers insights on how to balance strength, ductility, and density for specific applications. It also provides information on twinning behaviors, stacking faults, elastic properties, coating and film deposition methods, manufacturing challenges, and the use of computational techniques for alloy design.

This chapter provides an overview of the physical metallurgy of beryllium, discussing phases and phase transformations, physical and mechanical properties, heat treatment, and alloying. It explains how the atomic structure of beryllium, particularly its sp hybrid state, contributes to the anisotropy of elastic constants and slip properties, resulting in a specific stiffness, or modulus-to-density ratio, six times higher than that of any other structural material.

Tensile tests are performed for several reasons related to materials development, comparison, selection, and quality control. The properties derived from tensile tests are used in selecting materials for engineering applications. Tensile properties often are used to predict or estimate the behavior of a material under forms of loading other than uniaxial tension. This chapter provides a brief overview of tensile specimens and test machines, stress-strain curves, true stress and strain, and test methodology and data analysis.

This chapter reviews the fundamentals of stress, strain, and deformation and demonstrates some of the tools and techniques used to analyze how materials and structures respond to tension, compression, bending, and shear. It begins with an overview of the behavior of perfectly elastic and plastic materials and viscous substances. It then describes the stress-strain response of two- and three-dimensional solids, explaining how to determine principle stresses and strains using Mohr’s circle and how to derive equivalent stress and strain using the von Mises relationship. It then goes on to analyze the stress state of load-bearing members, pressurized tubes, and pin-loaded lugs, accounting for the effect of geometric discontinuities, such as cutouts, fillets, and holes, as well as cracks. It also explains how finite element methods are used to solve problems involving complex geometric and loading conditions.

This chapter introduces the basic concepts of mechanical design and its general relation with the properties derived from tensile testing. It begins with a description of the basic objective of product design. Next, a simple tie bar is used to illustrate the application of mechanical property data to material selection and design and to highlight the general implications for mechanical testing. Material subjected to the basic stress conditions is considered to establish design approaches and mechanical test methods, first in static loading and then in dynamic loading and aggressive environments. The chapter then briefly describes design criteria for some basic property combinations such as strength, weight, and costs as well as stiffness in tension. Additionally, it describes the processes involved in mechanical testing for stress at failure and elastic modulus. Finally, the chapter examines the correlation between hardness and strength.

This chapter provides a thorough review of the crystal structure of beryllium and its elastic, thermal, and nuclear properties. It also includes information on electrical and optical properties and an extensive amount of data in the form of tables and plots.

Product design requires an understanding of the mechanical properties of materials, much of which is based on tensile testing. This chapter describes how tensile tests are conducted and how to extract useful information from measurement data. It begins with a review of the different types of test equipment used and how they compare in terms of loading force, displacement rate, accuracy, and allowable sample sizes. It then discusses the various ways tensile measurements are plotted and presents examples of each method. It examines a typical load-displacement curve as well as engineering and true stress-strain curves, calling attention to certain points and features and what they reveal about the test sample and, in some cases, the cause of the behavior observed. It explains, for example, why some materials exhibit discontinuous yielding while others do not, and in such cases, how to determine when yielding begins. It also explains how to determine other properties via tensile tests, including ductility, toughness, and modulus of resilience.

This chapter focuses on some of the facts of mechanical properties of metals that must be understood to successfully undertake the task of failure analysis. The discussion begins by describing the causes and effects of elastic and plastic deformation followed by a section describing the effects of temperature variations on mechanical properties, both in tension and in compression. The nonlinear behavior of gray cast iron caused by the graphite flakes is then described. Finally, the effect of stress concentrations on high-strength metals is considered.

This chapter presents the fundamentals of tensile testing of fiber-reinforced polymer composites. Basic tensile testing of polymer composites is divided into lamina and laminate testing. The chapter focuses on tensile testing of laminates. It discusses the most common tensile test methods that have been standardized for fiber-reinforced composite materials. It also briefly reviews considerations in tensile testing of metal-matrix composites.

This appendix provides readers with worked solutions to 25 problems involving calculations associated with tensile testing and the determination of mechanical properties and variables. The problems deal with engineering factors and considerations such as stress and strain, loading force, sample lengthening, and machine stiffness, and with mechanical properties and parameters such as elastic modulus, Young’s modulus, strength coefficient, strain-hardening exponent, and modulus of resilience. They also cover a wide range of materials including various grades of aluminum and steel as well as iron, titanium, brass, and copper alloys.

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.

In dynamic hardness tests, the test force is applied to the defined indenter in an accelerated way (with a high application rate). Dynamic test methods relate hardness to the elastic response of a material, whereas the classical static indentation tests determine hardness in terms of plastic behavior. This chapter describes the most important and widespread dynamic hardness testing methods. These tests fall into two categories: methods in which the deformation is measured and methods in which the energy is measured. Methods that measure deformation include the Poldi hammer method, the shearing force method, the Baumann hammer method, and the Dynatest method. Methods that measure energy include the Shore method, the Leeb method, and the Nitronic method. The chapter concludes with a discussion of applications of dynamic hardness testing.

This chapter discusses the design and application of sheet forming presses. The discussion covers critical variables and design parameters, key components, basic machine configurations, and energy and load requirements. The chapter also discusses time-dependent characteristics, dimensional accuracy, and stiffness as well as die change procedures.

This article, prepared under the auspices of the ASM Thermal Spray Society Committees on Accepted Practices, describes a procedure for evaluating residual stresses in thermal spray coatings, which is an extension of the well-known layer removal method to include the Young’s modulus and Poisson’s ratio properties of the thermal spray coating material and the substrate. It presents questions and answers that were selected to introduce residual stresses in thermal spray coatings. The article describes equipment and the laboratory procedure for the modified layer removal method and provides the description of the residual stress specimen. It also describes the procedures for applying or installing bonded resistance strain gages, the dimensions of the test specimen, the procedure for removing layers, and the method for interpreting the data to evaluate residual stresses. The spreadsheet program, “ MLRM for Residual Stresses ,” is available as a supplement to this document.

Composite systems for cryogenic applications are discussed in this chapter. This chapter emphasizes filamentary-reinforced composites because they are the most widely used composite materials. It begins with a discussion on the approach to designing and fabricating with low-pressure laminate composites. This is followed by a section providing an overview of the materials in modern cryogenic technology. Then, the chapter describes the effect of cryogenic temperatures on materials properties; it also introduces the various joining techniques developed for composite materials. The effects of radiation on the properties of the materials are covered as well as the processes involved in testing laminates at cryogenic temperatures. Finally, the chapter provides information available on concrete aggregate composites.

Specific heat is a fundamental property that relates the total heat per unit mass added to a system to the resultant temperature change of the system. This chapter begins with the definition and historical development of specific heat. Thermodynamic and solid state relationships are presented which include discussions about lattice specific heat and the effects of magnetic and superconducting transitions. Data sources for practical applications and methods of estimating specific heat for materials are also included. The chapter concludes with a section concerning the measurement of specific heat at low temperatures.