This article provides a brief description of the different types of micromechanisms of monotonic and cyclic fracture. General information on the material variables that have the most beneficial effect on resistance to failure is presented. The article discusses the various stages, growth rates, and striation spacings of fatigue crack. The mechanisms of fatigue striation formation are also discussed. The fatigue crack growth in duplex microstructures and cyclic crack growth in polymers are reviewed. The article also describes the mechanisms and models of fatigue crack closure.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of miscellaneous metals and alloys and in identifying and interpreting the morphology of fracture surfaces. The metals and alloys covered include tungsten, iridium, magnesium-base, iron-base, molybdenum-base, and tantalum-base materials. The fractographs illustrate fatigue striations, slow-bending fracture, quasi-cleavage fracture, corrosion-fatigue fracture, fatigue crack, intergranular cleavage, microvoid coalescence, tension-overload fracture, crack propagation, impact fracture, and high-cycle fatigue failure.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of austenitic stainless steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the following: fatigue-crack fracture, rock candy fracture, cleavage fracture, brittle fracture, high-cycle fatigue fracture, fatigue striations, hydrogen-embrittlement failure, creep crack propagation, fatigue crack nucleation, intergranular creep fracture, torsional overload fracture, stress-corrosion cracking, and grain-boundary damage of these steels. The austenitic stainless steel components include spring wires, preheater-reactor slurry transfer lines and gas lines of coal-liquefaction pilot plants, oil feed tubes and suction couch rolls of paper machines, cortical screws and compression hip screws of orthopedic implants, and Jewett nails.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of nickel alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the fatigue crack, transgranular cleavage, intergranular fracture, grain boundaries, notch and fatigue precrack, dimpled rupture, and fatigue striations of these alloys.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of copper alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the following: fatigue fracture, intergranular fracture, transgranular fracture, microvoid coalescence, corrosion fatigue, fatigue striations, tensile-overload fracture, stress-corrosion cracking, and pitting corrosion of these alloys.

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 is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of polymers, including polycarbonate, polyethylene, and polyimide, and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the quasi-brittle fatigue crack propagation, brittle and ductile fracture, crack-growth mechanisms, tearing, fibrillation, and fatigue striations of these surfaces.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of ASTM/ASME alloy steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the solidification cracking, creep failure, brittle fracture, fracture by overpressurization, inclusion effect, fatigue crack propagation, ductile fatigue striation, secondary cracking, intergranular fracture, and elevated-temperature fracture of alloy steels used in pressure vessels, steam boiler superheater tubes, and box-girder bridges.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of wrought aluminum alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the corrosion-fatigue fracture, fatigue striations, tension-overload fracture surface, ductile fracture, cone-shaped fracture surface, intergranular crack propagation, transgranular crack propagation, stress-corrosion cracking, hydrogen damage, and grain-boundary separation of these alloys. Fractographs are also provided for a forged aircraft main-landing gear wheel and actuator beam, an aircraft wing spar, a fractured aircraft propeller blade, shot peened fillet, an aircraft lower-bulkhead cap, and clevis-attachment lugs.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of martensitic stainless steels and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the fracture surface, high-cycle fatigue fracture, tensile-shear fracture, intergranular crack, fatigue striations, and microvoid coalescence of conveyor-chain links, hub socket of aircraft propellers, and automotive intake valves of these steels.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of pure irons and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the grain-boundary cavitation; slip lines; intergranular fracture; cleavage fracture; notch-impact fracture; oxide inclusions and blowholes; ductile rupture; impact fracture and tensile-test fracture surfaces; fatigue striations; and crack initiation and propagation of pure irons.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of cast aluminum alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the brittle fracture, microvoid coalescence, fatigue striations, and microstructure of these alloys. The components considered include fractured sand-cast carrier trays, broken extension-housing yokes, helicopter tail-rotor drive assemblies, fractured bell-crank fittings, chain-hoist hooks, and automotive connecting rods.

Fatigue failure of engineering components and structures results from progressive fracture caused by cyclic or fluctuating loads. Fatigue is an important potential cause of mechanical failure, because most engineering components or structures are or can be subjected to cyclic loads during their lifetime. This article focuses on fractography of fatigue. It provides an abbreviated summary of fatigue processes and mechanisms: fatigue crack initiation, fatigue crack propagation, and final fracture,. Characteristic fatigue fracture features that can be discerned visually or under low magnification are then described. Typical microscopic features observed on structural metals are presented subsequently, followed by a brief discussion on fatigue in polymers and polymer-matrix composites.

This article illustrates typical fractographic features for a number of different composite materials. It describes the differences in fracture characteristics due to different loading, material processing, and environmental conditions. The article presents fractographic data obtained from epoxy matrix materials. Minimal fractographic data from other brittle thermoset resin systems are also presented. The article discusses the interlaminar fracture of composites with ductile thermoplastic matrices. It also provides information on the translaminar fracture features of the composite materials.

This article commences with a summary of fatigue processes and mechanisms. It focuses on fractography of fatigue. Characteristic fatigue fracture features that can be discerned visually or under low magnification are described. Typical microscopic features observed on structural metals are presented subsequently, followed by a brief discussion of fatigue in nonmetals. The article reviews the various macroscopic and microscopic features to characterize the history and growth rate of fatigue in metals. It concludes with a description of fatigue of polymers and composites.

This article commences with a description of the prosthetic devices and implants used for internal fixation. It describes the complications related to implants and provides a list of major standards for orthopedic implant materials. The article illustrates the body environment and its interactions with implants. The considerations for designing internal fixation devices are also described. The article analyzes failed internal fixation devices by explaining the failures of implants and prosthetic devices due to implant deficiencies, mechanical or biomechanical conditions, and degradation. Finally, the article discusses the fatigue properties of implant materials and the fractures of total hip joint prostheses.

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.

This article focuses on the analysis of materials and mechanical- (or biomechanical-) based medical device failures. It reviews the failure analysis practices, including evidence receipt, cleaning, nondestructive examination, destructive examination, exemplars analysis, and device redesign. The article examines the common failure modes, such as overload, fatigue, corrosion, hydrogen embrittlement, and fretting, of medical devices. The failure analysis of orthopedic implants, such as permanent prostheses and internal fixation devices, is described. The article reviews the failure mechanisms in some of the more common medical device materials, namely, stainless steels, titanium alloys, cobalt-base alloys, and nitinol. It presents case histories with examples for failure analysis.

This article illustrates the role that fracture mechanics can play in failure analysis. It describes the important failure criteria as relations between design and materials factors, which are used to correlate fracture mechanics analysis to the observations of a failure analysis. Descriptions include an indication of how the factors are typically evaluated. The article also provides information on subcritical fracture mechanics. Finally, a group of failure analysis examples explain how fracture mechanics parameters can be determined and how they may be fitted into an overall failure investigation.

As cast iron parts are extensively applied, fracture events will eventually take place. Consequently, it becomes essential to carry out failure analyses to identify the cause of fracture and to provide corrective actions that allow safe operation. This article presents a description of the main fracture modes and their characteristic fractographic features. It discusses the four principal fracture modes: dimple rupture (or fracture), cleavage, fatigue, and intergranular fracture. The article provides information on special cases of environmentally assisted fracture. It concludes with a description of fractographic analyses for identifying the direction of propagation of a crack.