This article reviews the various types of mechanical testing methods, including hardness testing; tension testing; compression testing; dynamic fracture testing; fracture toughness testing; fatigue life testing; fatigue crack growth testing; and creep, stress-rupture, and stress-relaxation testing. Shear testing, torsion testing, and formability testing are also discussed. The discussion of tension testing includes information about stress-strain curves and the properties described by them.

This article describes testing and characterization methods of ceramics for chemical analysis, phase analysis, microstructural analysis, macroscopic property characterization, strength and proof testing, thermophysical property testing, and nondestructive evaluation techniques. Chemical analysis is carried out by X-ray fluorescence spectrometry, atomic absorption spectrophotometry, and plasma-emission spectrophotometry. Phase analysis is done by X-ray diffraction, spectroscopic methods, thermal analysis, and quantitative analysis. Techniques used for microstructural analysis include reflected light microscopy using polarized light, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X-rays, and wavelength dispersive analysis of X-rays. Macroscopic property characterization involves measurement of porosity, density, and surface area. The article describes testing methods such as room and high-temperature strength test methods, proof testing, fracture toughness measurement, and hardness and wear testing. It also explains methods for determining thermal expansion, thermal conductivity, heat capacity, and emissivity of ceramics and glass and measurement of these properties as a function of temperature.

This article discusses the equipment design, procedures, experimental considerations, and interpretation of the torsion tests used to establish workability. It describes the application of torsion testing to obtain flow-stress data and to gage fracture-controlled workability and flow-localization-controlled failure. The article discusses the torsion test used to establish the processing parameters that are required to produce the desired microstructures.

This article begins with a discussion of the basic fracture modes, including dimple ruptures, cleavages, fatigue fractures, and decohesive ruptures, and of the important mechanisms involved in the fracture process. It then describes the principal effects of the external environment that significantly affect the fracture propagation rate and fracture appearance. The external environment includes hydrogen, corrosive media, low-melting metals, state of stress, strain rate, and temperature. The mechanism of stress-corrosion cracking in metals such as steels, aluminum, brass, and titanium alloys, when exposed to a corrosive environment under stress, is also reviewed. The final section of the article describes and shows fractographs that illustrate the influence of metallurgical discontinuities such as laps, seams, cold shuts, porosity, inclusions, segregation, and unfavorable grain flow in forgings and how these discontinuities affect fracture initiation, propagation, and the features of fracture surfaces.

Fracture surfaces are fragile and subject to mechanical and environmental damage that can destroy microstructural features. This article discusses the importance of care and handling of fractures and the factors that need to be considered during the preliminary visual examination. It describes the procedures for sectioning a fracture and opening secondary cracks as well as the effect of nondestructive inspection on subsequent evaluation. The article provides information on the most common techniques for cleaning fracture surfaces. These techniques are dry air blast cleaning, replica stripping, organic-solvent cleaning, water-base detergent cleaning, cathodic cleaning, and chemical-etch cleaning.

Mechanical properties are often the most important properties in the design and selection of engineering plastics. Temperature, molecular structure, crystallinity, viscoelasticity, and effects of environment, fillers and reinforcements are considered as the basic factors affecting the mechanical properties of engineering plastics. The testing methods for determining mechanical properties, including stress-strain test, modulus-directed tensile test, strength test, strength-directed tensile test, impact test, and dynamic mechanical test are discussed.

Stress-corrosion cracking (SCC) occurs under service conditions, which can result, often without any prior warning, in catastrophic failure. Hydrogen embrittlement is distinguished from stress-corrosion cracking generally by the interactions of the specimens with applied currents. To determine the susceptibility of alloys to SCC and hydrogen embrittlement, several types of testing are available. This article describes the constant extension testing, constant load testing, constant strain-rate testing for smooth specimens and precracked or notched specimens of SCC. It provides information on the cantilever beam test, wedge-opening load test, contoured double-cantilever beam test, three-point and four-point bend tests, rising step-load test, disk-pressure test, slow strain-rate tensile test, and potentiostatic slow strain-rate tensile test for hydrogen embrittlement.

This article introduces the principal methodologies and some advanced technologies that are being applied for nondestructive evaluation (NDE) of fiber-reinforced polymer-matrix composites. These include acoustic emission, ultrasonic, eddy-current, computed tomography, electromagnetic acoustic transducer, radiography, thermography, and low-frequency vibration methods. The article also provides information on NDE methods commonly used for metal-matrix composites.

This article focuses on the influence of various work material properties, namely, hardness; toughness; stiffness; ductility; thermal, electrical, and magnetic properties; and microstructure effects on finishing methods. It also addresses the relative response of work materials, such as metals, ceramics, and composites, to grinding.

Thermomechanical processing (TMP) refers to various metal forming processes that involve careful control of thermal and deformation conditions to achieve products with required shape specifications and good properties. This article describes TMP methods in producing hot-rolled steel and reviews how improvements in the strength and toughness depend on the synergistic effect of microalloy additions and on carefully controlled thermomechanical conditions. It discusses TMP variables and the general distinctions between conventional hot rolling and common types of controlled-rolling schedules. The article describes the metallurgical processes in grain refinement of austenite steel by hot working, such as recovery and recrystallization and strain-induced transformation. The grain refinement in high strength low alloy steel by alloy addition is also discussed. The article provides an outline on the key stages of deformation, and the required metallurgical information at each of these stages.

This article focuses on the factors that determine the extent of deformation a metal can withstand before cracking or fracture occurs. It informs that workability depends on the local conditions of stress, strain, strain rate, and temperature in combination with material factors. The article discusses the common testing techniques and process variables for workability prediction. It illustrates the simple and most widely used fracture criterion proposed by Cockcroft and Latham and provides a workability analysis using the fracture limit line. The article describes various workability tests, such as the tension test, ring compression test, plane-strain compression test, bend test, indentation test, and forgeability test. It concludes with information on the role of the finite-element modeling software used in workability analysis.

This article presents examples of the visual fracture examination that illustrate the procedure as it applies to failure analysis and quality determination. It describes the techniques and procedures for the visual and light microscopic examination of fracture surfaces with illustrations. The article also describes microscopic and macroscopic features of the different fracture mechanisms with illustrations with emphasis on visual and light microscopy examination. The types of fractures considered include ductile fractures, tensile-test fractures, brittle fractures, fatigue fractures, and high-temperature fractures.

The primary goal of failure analysis is to prevent the recurrence of product failures. This article discusses the sequence of activities in failure analysis and offers insight on how to gather background information, examine and assess damage, and identify the cause of the problem. It also explains where to look for evidence and how to collect samples for various types of testing. In addition, the article provides an introduction to fracture mechanics and explains how to predict and avoid fractures, including fatigue fracture, through testing and computational techniques.

The design process for ceramic materials is more complex than that of metals because of low-strain tolerance, low fracture toughness and brittleness. The application of structural ceramics to engineering systems hinges on the functional benefits to be derived and is manifested in the conceptual design for acceptable reliability. This article discusses the design considerations for the use of structural ceramics for engineering applications. It describes the conceptual design and deals with fast fracture reliability, lifetime reliability, joints, attachments, interfaces, and thermal shock in detailed design procedure. The article provides information on the proof testing of ceramics, and presents a short note on public domain software that helps determine the reliability of a loaded ceramic component. The article concludes with several design scenarios for gas turbine components, turbine wheels, ceramic valves, and sliding parts.

Wear of metals occurs by plastic displacement of surface and near-surface material, and by detachment of particles that form wear debris. This article presents a table that contains the classification of wear. It describes the testing and evaluation of wear and talks about the abrasive wear, lubrication and lubricated wear, and selection of steels for wear resistance. The article discusses the effect of alloying elements, composition, and mechanical properties of carbon and low-alloy steels at elevated temperatures. It talks about the fatigue resistance characteristics of steels, and describes the forms of embrittlement associated with carbon and low-alloy steels. The article provides information on the effect of composition, manufacturing practices, and microstructure on notch toughness of steels. Finally, it explains the effects of alloy elements, inclusion content, microstructure and heat treatment on fracture toughness of steels.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of maraging steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the tensile-test fracture, low-cycle fatigue fracture, fibrous fracture, crack-initiation zone, microvoid coalescence, fatigue-crack surface, hydrogen embrittlement, and fatigue striations of these steels.

This article provides information on the general characteristics, composition, uses, applications and specifications for standard grades of ductile iron. It describes the manufacturing and metallurgical process control procedures, including testing and inspection, and heat treatment. The article also talks about the effects of composition, graphite shape, and section size on the mechanical properties of ductile iron. Tables and graphs provide helpful information on the tensile properties, compressive properties, torsional properties, damping capacity, impact properties, fracture toughness, fatigue strength, and elevated-temperature properties of ductile iron.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of AISI/SAE alloy steels (4xxx steels) and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the brittle fracture, ductile fracture, impact fracture, fatigue fracture surface, reversed torsional fatigue fracture, transgranular cleavage fracture, rotating bending fatigue, tension-overload fracture, torsion-overload fracture, slip band crack, crack growth and crack initiation, crack nucleation, microstructure, hydrogen embrittlement, sulfide stress-corrosion failure, stress-corrosion cracking, and hitch post shaft failure of these steels. The components considered in the article include tail-rotor drive-pinion shafts, pinion gears, outboard-motor crankshafts, bull gears, diesel engine bearing cap bolts, splined shafts, aircraft horizontal tail-actuator shafts, bucket elevators, aircraft propellers, helicopter bolts, air flasks, tie rod ball studs, and spiral gears.

Workability is the ability of the workpiece metal to undergo extrusion or drawing without fracture or defect development. This article describes the limits of workability in extrusion and drawing in terms of fracture and flaw development and presents some comments on fracture mechanisms. It discusses the empirical projections of absolute workability from various mechanical tests. The article concludes with a discussion on extrusion and drawing process design implications.