Film radiography requires the development of the exposed film so that the latent image becomes visible for viewing. It describes the general characteristics of film, including speed, gradient, and graininess, and the factors affecting film selection and exposure time. The article discusses the three major inspection techniques for tubular sections, namely, the double-wall, double-image technique; the double-wall, single-image technique; and the single-wall, single-image technique. It illustrates the arrangements of penetrameters and identification markers for the radiography of plates, cylinders, and flanges. The article discusses various control methods, including the use of lead screens; protection against backscatter and scatter from external objects; and the use of masks, diaphragms, collimators, and filtration. The radiographic appearance of specific types of flaws is also discussed. The article concludes with a discussion on two methods of radiographic film processing: manual and automatic processing.

This article provides a discussion on general nondestructive evaluation (NDE) science and considerations for specific technique selection. It explains the basic concept of flaw detection and evaluation and probability of detection. The article provides an overview of NDE methods with their applications, limitations, and advantages. It includes details on NDE codes, calibration standards, inspection frequency, guidance on how to perform inspections, applicability, and mandatory and nonmandatory practice. The article also provides tips on where to focus inspections in order to align with the likely areas of damage or degradation and a number of other aspects of inspection.

Measuring the thickness of thin films can be accomplished in many ways. This article focuses on the optical method of single-wavelength ellipsometry, two multiple-wavelength methods of reflectometry and spectroscopic ellipsometry for measuring the thickness of thin films. The general capabilities, principles and applications of ellipsometry and reflectometry are discussed in terms of nondestructive methods.

This article discusses the principles and limitations of micromagnetic techniques, namely, magnetic Barkhausen noise (MBN) and magnetoacoustic emission (MAE). It also discusses various factors limiting the establishment of acceptance criteria for test components as they pertain to the successful application of MBN measurement and signal interpretation. The article provides an overview of basic magnetic phenomena and dynamics in ferromagnetic materials that underlie the origin of MBN emissions. It describes the changes in the domain structure of the ferromagnetic material under an applied external field. The relationship between uniaxial stress and angular-dependent strain is also discussed. The influence of stress on domain walls, and therefore, the generation of Barkhausen noise are described. The article also describes the directional and angular MBN measurements and provides information on detection, angular dependence, and advanced analysis methods of MBN emissions.

This article focuses on the metallography and microstructures of wrought and cast aluminum and aluminum alloys. It describes the role of major alloying elements and their effect on phase formation and the morphologies of constituents formed by liquid-solid and/or solid-state transformations. The article also describes specimen preparation procedures and examines the microstructure of several alloy samples.

This article provides a discussion on the metallographic techniques used for failure analysis, and on fracture examination in materials, with illustrations. It discusses various metallographic specimen preparation techniques, namely, sectioning, mounting, grinding, polishing, and electrolytic polishing. The article also describes the microstructure examination of various materials, with emphasis on failure analysis, and concludes with information on the examination of replicas with light microscopy.

Metallographic examination is one of the most important procedures used by metallurgists in failure analysis. Typically, the light microscope (LM) is used to assess the nature of the material microstructure and its influence on the failure mechanism. Microstructural examination can be performed with the scanning electron microscope (SEM) over the same magnification range as the LM, but examination with the latter is more efficient. This article describes the major operations in the preparation of metallographic specimens, namely sectioning, mounting, grinding, polishing, and etching. The influence of microstructures on the failure of a material is discussed and examples of such work are given to illustrate the value of light microscopy. In addition, information on heat-treatment-related failures, fabrication-/machining-related failures, and service failures is provided, with examples created using light microscopy.

This article illustrates the momentum-trapping scheme in the incident bar and stress-reversal technique which is used to change the strain rate during the course of Hopkinson bar compression or tension experiments. It describes techniques to recover the sample after it has been subjected to a cycle of compression followed by tension or tension followed by compression with illustrations. The article provides information on the recovery dynamic testing of hard materials such as ceramics and ceramic composites and explains high-temperature dynamic recovery tests. The recovery of the sample that has been subjected to a single stress pulse allows a number of interesting applications, a few of which are reviewed.

This article reviews the failure analysis process with specific reference to the considerations that should be addressed when a casting has failed. It describes the failure analysis methodology for three failed cast components: an aluminum bracket, a bronze suction roll, and a steel automotive spindle. The article discusses failure analysis investigation by obtaining casting background information, planning the evaluation and selecting the appropriate casting for analysis, conducting a preliminary examination, conducting the proper material evaluations, and thoroughly evaluating the test data. It concludes with information on case studies that show how the methodology is adapted for differing materials, failure mechanisms, and failure circumstances.

Tool steels are prepared for metallographic examination in the same way as carbon steels with a few variations owing to hardness and alloying differences. This article explains what makes tool steels different and how to compensate for it when sectioning, mounting, grinding, polishing, and etching. It provides information and data on composition, hot working, austenitizing, tempering, and powder metal manufacturing and explains how it affects tool steel microstructure, using more than 100 detailed images.

This article describes the test techniques that are available for monitoring crack initiation and crack growth and for obtaining information on fatigue damage in test specimens. These techniques include optical methods, the compliance method, electric potential measurement, and gel electrode imaging methods. The article discusses the magnetic techniques that are primarily used as inspection techniques for detecting fatigue cracks in structural components. It details the principles and operation procedures of the liquid penetrant methods, positron annihilation techniques, acoustic emission techniques, ultrasonic methods, eddy current techniques, infrared techniques, exoelectron methods, and gamma radiography. The article explains the microscopy methods used to determine fatigue crack initiation and propagation. These include electron microscopy, scanning tunneling microscopy, atomic force microscopy, and scanning acoustic microscopy. The article also reviews the X-ray diffraction technique used for determining the compositional changes, strain changes, and residual stress evaluation during the fatigue process.

This article covers the three most popular techniques used to characterize the very outermost layers of solid surfaces: Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Some of the more important attributes are listed for preliminary insight into the strengths and limitations of these techniques for chemical characterization of surfaces. The article describes the basic theory behind each of the different techniques, the types of data produced from each, and some typical applications. Also discussed are the different types of samples that can be analyzed and the special sample-handling procedures that must be implemented when preparing to do failure analysis using these surface-sensitive techniques. Data obtained from different material defects are presented for each of the techniques. The examples presented highlight the typical data sets and strengths of each technique.

X-ray topography is the general term for a family of x-ray diffraction imaging techniques capable of providing information on the nature and distribution of imperfections. This article provides a detailed account of x-ray topography techniques, providing information on the historical background and development trends in x-ray diffraction topography. The discussion covers the general principles, components of systems, and applications of x-ray topography techniques, namely conventional X-ray topographic techniques and synchrotron x-ray topographic techniques.

A major portion of microstructural analysis of magnetic materials has centered on examination of optical, electron, and scanning probe metallographic techniques. This article reviews the methods pertaining to the microstructural examination of bulk magnetic materials, including microscopy techniques specific to magnetic materials (e.g., domain imaging), with specific examples where possible. It includes metallographic sample preparation procedures, followed by descriptions of microstructures of bulk magnetic materials. Information on magnetically soft materials, permanent magnets, magnetism and magnetic domains is also included. Finally, the article discusses microscopy techniques unique to magnetic materials characterization. Techniques used in the study of magnetic domain structures (microstructure) include the magneto-optical Kerr method, the Faraday method, and the Bitter technique. Scanning electron microscopy (magnetic contrast Types I and II), scanning electron microscopy with polarization analysis, Lorentz transmission electron microscopy, and magnetic force microscopy are also examined.

Spark source mass spectrometry (SSMS) is an analytical technique used for determining the concentration of elements in a wide range of solid samples, including metals, semiconductors, ceramics, geological and biological materials, and air and water pollution samples. This article discusses the basic principles of spark source technique; SSMS instrumentation such as ion source, electric sector, and magnetic sector; sample preparation; and test procedures of SSMS. Some of the related techniques to SSMS are laser ionization mass spectrometry and laser-induced resonance ionization mass spectrometry. The ions produced in SSMS are detected by either the photometric method or electrical detection method and quantitatively measured by techniques such as internal standardization techniques, isotope dilution, multi element isotope dilution, and dry spike isotope dilution. The detected spark source spectrum contains all the elemental data of the tested sample. Finally, the article exemplifies the applications of SSMS.

Proper sectioning of the surface to be examined is a very important step in preparing steel specimens. The first step in preventing damage to the metallurgical structure is to minimize the amount of sectioning that is done. This article discusses the various metallographic techniques, namely mounting, grinding, polishing, and etching involved in the microstructural analysis of carbon and alloy steels, case hardening steels, cast iron, ferrous powder metallurgy alloys, wrought and cast stainless steels, tool materials, steel castings, iron-chromium-nickel heat-resistant casting alloys and different product forms of steels.

This article briefly discusses popular techniques for metals characterization. It begins with a description of the most common techniques for determining chemical composition of metals, namely X-ray fluorescence, optical emission spectroscopy, inductively coupled plasma optical emission spectroscopy, high-temperature combustion, and inert gas fusion. This is followed by a section on techniques for determining the atomic structure of crystals, namely X-ray diffraction, neutron diffraction, and electron diffraction. Types of electron microscopies most commonly used for microstructural analysis of metals, such as scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy, are then reviewed. The article contains tables listing analytical methods used for characterization of metals and alloys and surface analysis techniques. It ends by discussing the objective of metallography.

This article discusses the inspection/reference standards that are absolutely critical for proper application of ultrasonic inspection systems. Many of the standards and specifications for ultrasonic inspection require the use of standard reference blocks. The article lists the variables that should be considered when selecting standard reference blocks and describes the three types of standard blocks ordinarily used for calibration or reference: area-amplitude blocks, distance-amplitude blocks, and blocks of the type sanctioned by the International Institute of Welding. It reviews the determination of area-amplitude and distance-amplitude curves of a straight-beam pulse-echo ultrasonic inspection system. The article discusses the three principal conventional manual ultrasonic sizing techniques: 6 dB drop technique, maximum-amplitude technique, and 20 dB drop technique. It provides information on the dimension-measurement applications of ultrasonic inspection methods.

Additive manufacturing (AM) is the process of joining materials to make parts from three-dimensional (3D) model data, usually layer upon layer, as opposed to subtractive manufacturing and formative manufacturing methodologies. This article discusses various defects in AM components, such as porosity, inclusions, cracking, and residual stress, that can be avoided by using vendor recommended process parameters and approved materials. It describes the development of process-structure-property-performance modeling. The article explains the practical considerations in nondestructive evaluation for additively manufactured metallic parts. It also examines nondestructive testing (NDT) inspection and characterization methods for each of the manufacturing stages in their natural order. The article provides information on various inspection techniques for completed AM manufactured parts. The various electromagnetic and eddy current techniques that can be used to detect changes to nearsurface geometric anomalies or other defects are also discussed. These include ultrasonic techniques, radiographic techniques, and neutron imaging.

Failure analysis is an investigative process that uses visual observations of features present on a failed component fracture surface combined with component and environmental conditions to determine the root cause of a failure. The primary means of recording the conditions and features observed during a failure analysis investigation is photography. Failure analysis photographic imaging is a combination of both science and art; experience and proper imaging techniques are required to produce an accurate and meaningful fracture surface photograph. This article reviews photographic principles and techniques as applied to failure analysis, both in the field and in the laboratory. The discussion covers the processes involved in field and laboratory photographic documentations, provides a description of professional digital cameras, and gives information on photographic lighting and microscopic photography. Special techniques can be employed to deal with highly reflective conditions and are also described in this article.