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Series: ASM Handbook
Volume: 9
Publisher: ASM International
Published: 01 December 2004
DOI: 10.31399/asm.hb.v09.a0003755
EISBN: 978-1-62708-177-1
..., and vacuum system. It discusses the contrasts mechanisms used for imaging and analyzing materials in the SEM. These include the topographic contrast, compositional contrast, and electron channeling pattern and orientation contrast. Special instrumentation and accessory equipment used at elevated pressures...
Abstract
This article outlines the beam/sample interactions and the basic instrumental design of a scanning electron microscopy (SEM), which include the electron gun, probeforming column (consisting of magnetic electron lenses, apertures, and scanning coils), electron detectors, and vacuum system. It discusses the contrasts mechanisms used for imaging and analyzing materials in the SEM. These include the topographic contrast, compositional contrast, and electron channeling pattern and orientation contrast. Special instrumentation and accessory equipment used at elevated pressures and during the X-ray microanalysis are reviewed. The article also provides information on the sample preparation procedure and the materials applications of the SEM.
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006668
EISBN: 978-1-62708-213-6
... electron (BE) collection variations due to line of sight that produces topographic contrast during scanning electron microscope imaging. Position (1) produces more signal intensity than position (2). Fig. 30 Illustration of secondary electron (SE) emission variations for (a) low- and (b) high...
Abstract
This article provides detailed information on the instrumentation and principles of the scanning electron microscope (SEM). It begins with a description of the primary components of a conventional SEM instrument. This is followed by a discussion on the advantages and disadvantages of the SEM compared with other common microscopy and microanalysis techniques. The following sections cover the critical issues regarding sample preparation, the physical principles regarding electron beam-sample interaction, and the mechanisms for many types of image contrast. The article also presents the details of SEM-based techniques and specialized SEM instruments. It ends with example applications of various SEM modes.
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006644
EISBN: 978-1-62708-213-6
... surface for σ and π polarization states Fig. 2 Orientation contrast arising from misoriented regions. (a) Monochromatic radiation (beam divergence < misorientation). (b) Monochromatic radiation (beam divergence > misorientation). (c) Continuous radiation. (d) Reflection topograph from...
Abstract
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.
Book: Surface Engineering
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001300
EISBN: 978-1-62708-170-2
.... However, back-scattered electron emission is highly directional, and strong topographic contrast is visible for rough surfaces, depending on the position of the detector. Secondary electrons leave from the near-surface region of the sample when energies are less than approximately 50 eV and show...
Abstract
This article describes the structure of coatings produced by plasma spraying, vapor deposition, and electrodeposition processes. The main techniques used for microstructure assessment are introduced. The relationship between the microstructure and property is also discussed. The experimental techniques for microstructural characterization include metallographic technique, X-ray diffraction, electron, microscopies, and porosimetry.
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001760
EISBN: 978-1-62708-178-8
... the origin of contrast in a reflection topograph of a highly distorted crystal. For example, if a white (polychromatic) beam of x-rays from a point source impinges on a crystal surface, any imperfections that introduce tilts between adjacent regions cause the reflected rays to overlap partially ( Fig. 2a...
Abstract
X-ray topography is a technique that comprises topography and x-ray diffraction. This article provides a description of the kinematical theory and the dynamical theory of diffraction. It provides useful information on the configurations of reflection and transmission topography. The article explains various topographic methods, namely, divergent beam method, polycrystal rocking curve analysis, line broadening analysis, microbeam method, and polycrystal scattering topography, as well as their instrumentation. It also describes the applications of x-ray topography.
Series: ASM Handbook
Volume: 23
Publisher: ASM International
Published: 01 June 2012
DOI: 10.31399/asm.hb.v23.a0005685
EISBN: 978-1-62708-198-6
... This method produces a three-dimensional image by creating brightness contrast on very minor topographical changes. Differential interference contrast uses crossed polarizers, as described for polarized light. A double-quartz prism is also inserted into the light path to split the incident light into two...
Abstract
This article focuses on the modes of operation, physical basis, sample requirements, properties characterized, advantages, and limitations of the characterization methods used to evaluate the physical morphology and chemical properties of component surfaces for medical devices. These methods include light microscopy, scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy.
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006769
EISBN: 978-1-62708-295-2
... be observed in the secondary electron or compositional BSE images. In many instruments, a topographical mode subtracts signals from different BSE sensors to reduce composition contrast. The bias on the secondary electron detector can also be varied on some instruments to obtain a highly directional BSE image...
Abstract
The scanning electron microscope (SEM) is one of the most versatile instruments for investigating the microscopic features of most solid materials. The SEM provides the user with an unparalleled ability to observe and quantify the surface of a sample. This article discusses the development of SEM technology and operating principles of basic systems of SEM. The basic systems covered include the electron optical column, signal detection and display equipment, and the vacuum system. The processes involved in the preparation of samples for observation using an SEM are described, and the application of SEM in fractography is discussed. The article covers the failure mechanisms of ductile failure, brittle failure, mixed-mode failure, and fatigue failure. Lastly, image dependence on microscope type and operating parameters is also discussed.
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006763
EISBN: 978-1-62708-295-2
... or cleaning of the failed component will be required. This process typically involves examination with the unaided eye and proceeds to higher magnification. A handheld magnifier may be of assistance in the early examination. Because diffused lighting tends to decrease both contrast and topographic detail...
Abstract
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.
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006851
EISBN: 978-1-62708-395-9
... to higher magnification, either with a handheld magnifier or, ideally, a stereoscope. Because diffused lighting tends to decrease both contrast and topographic detail, oblique/tangential lighting at varying angles and orientations is often useful in visually evaluating the fracture features that are present...
Abstract
Failure analysis is an investigative process in which the visual observations of features present on a failed component and the surrounding environment are essential in determining the root cause of a failure. This article reviews the basic photographic principles and techniques that are applied to failure analysis, both in the field and in the laboratory. It discusses the processes involved in visual examination, field photographic documentation, and laboratory photographic documentation of failed components. The article describes the operating principles of each part of a professional digital camera. It covers basic photographic principles and manipulation of settings that assist in producing high-quality images. The need for accurate photographic documentation in failure analysis is also presented.
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003527
EISBN: 978-1-62708-180-1
... is beneficial in referencing component placement and orientation within an assembly during later parts of the investigation. Photographic lighting in the field should avoid harsh shadows that result in excessive contrast. Harsh shadows can be minimized by use of fill-flash. Component Identification...
Abstract
This article reviews photographic principles, namely, visual examination, field photographic documentation, and laboratory photographic documentation, as applied to failure analysis and the specific techniques employed in both the field and laboratory. It provides information on the photographic equipment used in failure analysis and on film and digital photography. The article describes the basics of photography and the uses of different types of lighting in photography of a fractured surface. The article also addresses the techniques involved in macrophotography and microscopic photography as well as other special techniques.
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003533
EISBN: 978-1-62708-180-1
... requires that the sample be electrically conductive to prevent a charge buildup in the sample that affects the incoming primary and emitted secondary electrons, resulting in a poor, distorted image that is constantly changing in contrast and location. The sample should also be dry when placed in the vacuum...
Abstract
The scanning electron microscopy (SEM) is one of the most versatile instruments for investigating the microstructure of metallic materials. This article highlights the development of SEM technology and describes the operation of basic systems in an SEM, including the electron optical column, signal detection and display equipment, and vacuum system. It discusses the preparation of samples for observation using an SEM and describes the application of SEM in fractography. If the surface remains unaffected and undamaged by events subsequent to the actual failure, it is often a simple matter to determine the failure mode by the use of an SEM. In cases where the surface is altered after the initial failure, the case may not be so straightforward. The article presents typical examples that illustrate these points. Image dependence on the microscope type and operating parameters is also discussed.
Book Chapter
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006671
EISBN: 978-1-62708-213-6
... by an oblique light source. This image shows three-dimensional topographic features. Higher-atomic-number areas and less electrically conductive microstructural features will appear brighter on polished and etched section samples and, to a lesser extent, topographic samples. Compositional contrast...
Abstract
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.
Book Chapter
Book: Fractography
Series: ASM Handbook
Volume: 12
Publisher: ASM International
Published: 01 January 1987
DOI: 10.31399/asm.hb.v12.a0001836
EISBN: 978-1-62708-181-8
.... The tensile strength of the material was 586 MPa (85 ksi). In this area, the fracture surface shows well-defined fatigue striations that are clearly visible in both the SEM and the TEM pairs but with more detail and contrast in the TEM. Note the excellent match of the reproductions made by the two techniques...
Abstract
The application of transmission electron microscope to the study of fracture surfaces and related phenomena has made it possible to obtain magnifications and depths of field much greater than those possible with light (optical) microscopes. This article reviews the methods for preparing single-stage, double-stage, and extraction replicas of fracture surfaces. It discusses the types of artifacts and their effects on these replicas, and provides information on shadowing of replicas. The article concludes with a comparison of the transmission electron and scanning electron fractographs with illustrations.
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006765
EISBN: 978-1-62708-295-2
... contrast or topographic contrast is strong, the SEM provides good structural images, particularly above 500× ( Ref 1 ). Again, because of the limitations and advantages of each instrument, they are complementary rather than competitive tools. Metallographic Specimen Preparation Sectioning Mounting...
Abstract
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.
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006633
EISBN: 978-1-62708-213-6
... 392 , 2001 , p 75 – 84 10.1016/S0040-6090(01)00903-8 45. Bhushan B. and Qi J. , Phase Contrast Imaging of Nanocomposites and Molecularly-Thick Lubricant Films in Magnetic Media , Nanotechnology , Vol 14 , 2003 , p 886 – 895 10.1088/0957-4484/14/8/309 46. Kasai T...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006759
EISBN: 978-1-62708-295-2
... contrast can be used to determine the location of pristine metal or unobscured fracture features amidst surface contamination, while SE imaging provides topographical information for determining the failure mechanism in those unobscured areas. Figure 3 shows microvoid coalescence (MVC) amidst a corrosion...
Abstract
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.
Series: ASM Handbook
Volume: 12
Publisher: ASM International
Published: 01 January 1987
DOI: 10.31399/asm.hb.v12.9781627081818
EISBN: 978-1-62708-181-8
Book: Surface Engineering
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001237
EISBN: 978-1-62708-170-2
... optically anisotropic metals, such as beryllium, α-titanium, and zirconium. Differential interference contrast (DIC) illumination is used to enhance topographic features in a surface. DIC illumination uses a Nomarski-modified Wollaston prism to split light into two wavefronts. Along with a polarizer...
Abstract
Quantitative image analysis has expanded the capabilities of surface analysis significantly with the use of computer technology. This article provides an overview of the quantitative image analysis and optical microscopy. It describes the various steps involved in surface preparation of samples prone to abrasion damage and artifacts for quantitative image analysis.
Series: ASM Handbook
Volume: 9
Publisher: ASM International
Published: 01 December 2004
DOI: 10.31399/asm.hb.v09.a0003769
EISBN: 978-1-62708-177-1
... subsequently), the precipitates form a networklike morphology by solidifying around the α grains. In contrast, solid-state processes tend to produce a more dispersed second phase, such as those shown in Fig. 5 at various levels of magnification. Fig. 3 Aluminum corner of the aluminum-copper phase...
Abstract
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.
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003536
EISBN: 978-1-62708-180-1
... information regarding the microstructural features and failure mechanisms that govern the material fracture. The objective of quantitative fractography is to describe the geometric attributes of the topographic and microstructural features present in the fracture surface in quantitative terms, such as number...
Abstract
The quantitative characterization of fracture surface geometry, that is, quantitative fractography, can provide useful information regarding the microstructural features and failure mechanisms that govern material fracture. This article is devoted to the fractographic techniques that are based on fracture profilometry. This is followed by a section describing the methods based on scanning electron microscope fractography. The article also addresses procedures for three-dimensional fracture surface reconstruction. In each case, sufficient methodological details, governing equations, and practical examples are provided.