Examination of fatigue crack plastic zones using scanning-electron-microscope-based electron diffraction techniques
Two new scanning-electron-microscope-based electron diffraction techniques for examining strain fields in plastic zones associated with fatigue cracks are described. Electron channelling contrast imaging (ECCI) revealed the size and shape of the plastic zone much more swiftly and completely than an...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1996
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| Summary: | Two new scanning-electron-microscope-based electron diffraction techniques for examining strain fields in plastic zones associated with fatigue cracks are described. Electron channelling contrast imaging (ECCI) revealed the size and shape of the plastic zone much more swiftly and completely than an existing method which uses the degradation of electron channelling patterns (ECPs). Furthermore the sense of the lattice plane tilting can be deduced from the sense of the contrast seen in ECCI images. The shift in the position of zone axes in electron back-scatter diffraction (EBSD) patterns can be used to measure the extent of the lattice plane tilting and so provides quantitative information about the strains within the plastic zone. The advantages in the complementary ECCI and EBSD techniques over the ECP method are demonstrated through direct comparison of results obtained from studies of a fatigue-cracked superalloy. |
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