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EBSD With FEGSEM - Issues, Advances and Applications

Published online by Cambridge University Press:  02 July 2020

F.J. Humphreys
Affiliation:
Manchester Materials Science Centre, Grosvenor Street, Manchester, M1 7HS, UK
I. Brough
Affiliation:
Manchester Materials Science Centre, Grosvenor Street, Manchester, M1 7HS, UK
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A standard commercial EBSD system, comprising a CCD camera (Nordif) and acquisition software (HKL Technology) has been interfaced to a Philips XL30 FEGSEM, and the spatial and angular resolutions for EBSD compared with a conventional W-filament JEOL 6300 SEM equipped with a similar EBSD system.

In characterising a grain or subgrain structure, overlapping diffraction patterns are obtained at the boundaries, and the effective spatial resolution can be defined as the distance over which the patterns cannot be solved. The spatial resolution is best in the direction parallel to the specimen tilt axis (LA), typically some three times better than for the direction perpendicular to the axis. The resolution is conveniently determined by measuring the fraction of patterns which are solved (Ns) during a raster scan of the sample. For a microstructure of equiaxed grains of size D, LA is given approximately by D(1-Ns)/4. Figure 1 is a plot of Ns against D−1 for aluminium samples under optimum operating conditions, and it is seen that the spatial resolution in the FEGSEM is some three times better than in the W-filament SEM.

The effect of beam current on LA is shown in figure 2. For the W-filament SEM, LA is a strong function of the probe current.

Type
Electron diffraction in the SEM: automated EBSP and its application
Copyright
Copyright © Microscopy Society of America

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References

references

1.Humphreys, I.F.J., Huang, Y., Brough, I. and Harris, C.. “EBSD of grain and subgrain structures -Resolution considerations”. J. Microscopy, (in press).Google Scholar
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