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Cast Iron and Steels: Metallography
| Content Provider | Scilit |
|---|---|
| Author | Voort, George F. Vander |
| Copyright Year | 2016 |
| Description | Light optical microscopy (LOM) is, and has been, widely used to examine the microstructure of specimens. It should always be used first, starting at the lowest magnification and working to higher magnification, to correctly characterize the microstructure before deciding if it is necessary to use electron metallographic instruments to positively identify constituents by composition and/or formulae, or to observe the structure at higher magnification. Too often, the LOM is ignored and the engineer or technician goes to the scanning electron microscope (SEM) and immediately starts examination at high magnifications.The contrast mechanisms in SEM imaging are different than those of the LOM; SEM micrographs at magnifications ≤1000× are usually markedly inferior to LOM micrographs at the same magnification. Furthermore, SEM cannot take advantage of color etched images, which are frequently superior to B&W etchants at revealing microstructural information. Of course, many metallographers do not have x-ray diffraction or sophisticated electron metallographic equipment that can be used to produce positive identification of phases in metals and alloys, such as steels. Electron backscatter diffraction (EBSD), an attachment for the SEM (and now for the transmission electron microscope (TEM)), is an exceptionally powerful tool for microstructural characterization, but is not widely available outside of universities and sophisticated research laboratories. Instead, most metallographers must rely upon observations by light microscopy, perhaps aided by the use of selective etchants and microindentation hardness testing, plus their knowledge of the composition and processing of the material examined to determine what constituents or phases are present. This entry summarizes these techniques and illustrates the use of different illumination methods, plus color or selective etchants to assist the metallographer. Book Name: Encyclopedia of Iron, Steel, and Their Alloys |
| Related Links | https://api.taylorfrancis.com/content/chapters/edit/download?identifierName=doi&identifierValue=10.1081/E-EISA-120052826&type=chapterpdf |
| Ending Page | 689 |
| Page Count | 26 |
| Starting Page | 664 |
| DOI | 10.1081/e-eisa-120052826 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 2016-01-13 |
| Access Restriction | Open |
| Subject Keyword | Book Name: Encyclopedia of Iron, Steel, and Their Alloys Microstructure Magnification Constituents Metallographic Etchants Microscopy Widely |
| Content Type | Text |
| Resource Type | Chapter |
