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topographic contrast

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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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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
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...
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...
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...