Several qualitative, semiquantitative, and quantitative tests are available to estimate and control metal cleanliness, particularly inclusion concentration of aluminum alloys. This article provides a description of a few of the metal cleanliness assessment techniques, such as chemical analysis, pressure filter tests, electric resistivity tests, reduced-pressure test, and ultrasonic technique. Detection methods based on the certain principles and the types of impurities in chemical analysis are discussed.

This article describes some of the common elemental composition analysis methods and explains the concept of referee and economy test methods in failure analysis. It discusses different types of microchemical analyses, including backscattered electron imaging, energy-dispersive spectrometry, and wavelength-dispersive spectrometry. The article concludes with information on specimen handling.

Chemical analysis is a critical part of any failure investigation. With the right planning and proper analytical equipment, a myriad of information can be obtained from a sample. This article presents a high-level introduction to techniques often used for chemical analysis during failure analysis. It describes the general considerations for bulk and microscale chemical analysis in failure analysis, the most effective techniques to use for organic or inorganic materials, and examples of using these techniques. The article discusses the processes involved in the chemical analysis of nonmetallics. Advances in chemical analysis methods for failure analysis are also covered.

Ultrasonic inspection is a nondestructive method in which beams of high-frequency acoustic energy are introduced into a material to detect surface and subsurface flaws, to measure the thickness of the material, and to measure the distance to a flaw. This article provides a detailed account of ultrasonic flaw detectors, including ultrasonic transducers and types of search units and couplants. The article describes pulse-echo and transmission inspection methods and data interpretation. The general characteristics of ultrasonic waves and the factors influencing ultrasonic inspection are also addressed. The article concludes with a review of the advantages and disadvantages of ultrasonic inspection compared with other methods applications of the technique.

A variety of electrochemical techniques are used to detect and monitor material deterioration in service or in the field. This article describes the static or direct current measurements in a number of applications, including buried pipelines and storage tanks. It reviews the electrochemical impedance spectroscopy and electrochemical noise measurements in a laboratory, especially for the inspection of coatings.

This article considers the two primary methods used for ultrasonic inspection: pulse-echo and the transmission methods. Pulse-echo inspection can be accomplished with longitudinal, shear, surface (Rayleigh), or Lamb (plate) waves using a diverse range of transducers. The article discusses the principles of each of these inspection methods. It describes the applications and the basic data formats for single-element transducer-based systems, including A-scans, B-scans, and C-scans. The article provides information on electronic equipment used for ultrasonic inspection. It also describes how specific material conditions produce and modify A-scan indications. The article provides information on the controls and their functions for the display unit of the electronic equipment. It describes the techniques used for the identification and characterization of flaws, namely, surface (Rayleigh) wave and ultrasonic polar scan techniques.

This article presents a summary of the chemical fundamentals, general techniques, limitations, and applications of chemical spot testing as well as a brief overview of innovations and specialized applications. A list of selected reagents, including abbreviated instructions for preparing the reagent solution(s), for performing the spot test, and for interpreting the results, is also included. The article discusses two specialized applications of qualitative analysis, namely illicit drug identification and spacecraft drinking water quality testing. It also contains tables listing common presumptive tests for detecting anions and cations in aqueous solution.

This article reviews analytical techniques that are most often used in plastic component failure analysis. The description of the techniques is intended to familiarize the reader with the general principles and benefits of the methodologies, namely Fourier transform infrared spectroscopy, energy-dispersive x-ray spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The article describes the methods for molecular weight assessment and mechanical testing to evaluate plastics and polymers. The descriptions of the analytical techniques are supplemented by a series of case studies to illustrate the significance of each method. The case studies also include pertinent visual examination results and the corresponding images that aided in the characterization of the failures.

Corrosion is the deterioration of a material by a reaction of that material with its environment. The realization that corrosion control can be profitable has been acknowledged repeatedly by industry, typically following costly business interruptions. This article describes the electrochemical nature of corrosion and provides the typical analysis of environmental- and corrosion-related failures. It presents common methods of testing of laboratory corrosion and discusses the processes involved in the prevention of environmental- and corrosion-related failures of metals and nonmetals.

This article focuses on friction and wear of automotive and aircraft brakes. It provides a comparison of friction and wear behaviors, frictional characteristics, and frictional performance of the friction materials. The article describes the components of brake friction materials and the classifications of brake lining materials. It discusses the effect of formulation compositions and manufacturing processes and the effect of braking operation conditions. The article provides information on aircraft brake linings, which operate under a wide range of kinetic energy conditions. The morphology effect of graphite on automotive brake drum and disk is explained. The article also describes the characteristics of specific wear rates for both normal and local cast iron in automotive brake drums and disk rotors. It provides information on noises, vibrations, and harshness caused by brake pads. The article concludes with information on physical and chemical testing of brakes and toxicity of brake formulation and regulations.

This article focuses on the corrosion fatigue testing of steel in high-temperature water and discusses critical experimental issues associated with it. It provides information on the fundamental aspects of environmental crack advancement in general. The article explains the concepts and role of environmentally assisted crack growth in corrosion fatigue. It also discusses the fatigue test methods, including crack initiation testing and crack propagation testing. The article describes the specific types and influence rankings of experimental variables in corrosion fatigue.

This article discusses several aspects of biocompatibility of polymers, including the selection of a suitable polymer, specific use of a material, contact of polymer on body site, and duration of the contact. It describes the factors influencing the biological response of the polymer from a biocompatibility perspective. These include raw materials, the manufacturing process, cleaning and sterilization processes, and biodegradation and biostability. The article reviews the general testing methods of polymers, such as chemical, mechanical and thermal. It concludes with a section on the guidance, provided by the regulatory authorities, on the biocompatibility testing of polymers and polymer-containing devices that can aid in selecting the right analysis.

This article reviews the origins and development of scratch tests, the experimental configurations used in these tests, and the application of the tests to characterize the mechanical response of materials. It provides information on the measurement of indentation hardness. The article describes the important parameters of the scratch test. Finally, it discusses the sliding indentation fracture process of brittle materials.

The characterization, testing, and nondestructive evaluation of ceramics and glasses are vital to manufacturing control, property improvement, failure prevention, and quality assurance. This article provides a broad overview of characterization methods and their relationship to property control, both in the production and use of ceramics and glasses. Important aspects covered include the means for characterizing ceramics and glasses, the corresponding rationale behind them, and relationship of chemistry, phases, and microconstituents to engineering properties. The article also describes the effects that the structure of raw ceramic materials and green products and processing parameters have on the ultimate structure and properties of the processed piece. The effects that trace chemistry and processing parameters have on glass properties are discussed. The article describes mechanical tests and failure analysis techniques used for ceramics.

This article uses metal and alloy powders as examples to briefly discuss how to perform the characterization of powders. It begins by reviewing some of the techniques involved in the sampling of powders to ensure accurate characterization. This is followed by a discussion on the important properties to characterize powders, namely the particle size, surface area, density, porosity, particle hardness, compressibility, green strength, and flowability. For characterization of powders, both individual particles and bulk powders are used to evaluate their physical and chemical properties. The article also discusses the important characteristics and compositions of powder as well as impurities that directly affect powder properties. It ends with a description of the ignition and dust-explosion characteristics of organic and metal powders.

This article presents the structural attributes and internal characteristics of spot welds as well as the commonly inspected imperfections in resistance welds. It describes the industrial requirements for weld quality. Commonly performed destructive evaluations, namely, manual testing, quasi-static mechanical tests, dynamic mechanical tests, and metallographic examination, are reviewed. The article reviews weld-quality monitoring using various process signals and provides a discussion on the on-line and off-line nondestructive evaluation methods of spot weld quality.

Identification of alloys using quantitative chemical analysis is an essential step during a metallurgical failure analysis process. There are several methods available for quantitative analysis of metal alloys, and the analyst should carefully approach selection of the method used. The choice of appropriate analytical techniques is determined by the specific chemical information required, the condition of the sample, and any limitations imposed by interested parties. This article discusses some of the commonly used quantitative chemical analysis techniques for metals. The discussion covers the operating principles, applications, advantages, and disadvantages of optical emission spectroscopy (OES), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray spectroscopy, and ion chromatography (IC). In addition, information on combustion analysis and inert gas fusion analysis is provided.

This article reviews the fatigue and fracture properties of aluminum alloy castings, specifically alloys A356 and A357/D357 (all-T6) and alloy A201-T7, from the perspective of both design and manufacturing considerations. In addition, it provides an overview of the roles played by microstructure, manufacturing processes, test conditions, and casting design in determining the fatigue and fracture properties of aluminum casting alloys.

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 interaction of an implant with the human body environment may result in degradation of the implant, called corrosion. This article discusses the corrosion testing of metallic implants and implant materials. The corrosion environments for medical implants are the extracellular human body fluids, very complex solutions containing electrolytes and nonelectrolytes, inorganic and organic constituents, and gases. The article describes the fundamentals of electrochemical corrosion testing and provides a brief discussion on various types of corrosion tests. It illustrates corrosion current density determination by Tafel extrapolation, potentiodynamic measurement of the polarization resistance, electrochemical impedance measurement, and potentiostatic deaeration. Tests combining corrosion and mechanical forces, such as fretting corrosion tests, environment-assisted cracking tests, and ion-leaching tests are also discussed.