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Introduction
Electron
Backscatter Diffraction (EBSD) is a technique which allows crystallographic
information to be obtained from samples in the scanning electron microscope
(SEM). In EBSD a stationary electron beam strikes a tilted crystalline sample
and the diffracted electrons form a pattern on a fluorescent screen. This
pattern is characteristic of the crystal structure and orientation of the sample
region from which it was generated. The diffraction pattern can be used to measure the crystal orientation, measure grain boundary misorientations,
discriminate between different materials, and provide information about local
crystalline perfection. When the beam is scanned in a grid across a
polycrystalline sample and the crystal orientation measured at each point, the
resulting map will reveal the constituent grain morphology, orientations, and
boundaries. This data can also be used to show the preferred crystal
orientations (texture) present in the material. A complete and quantitative
representation of the sample microstructure can be established with EBSD.
In the last ten
years EBSD has become a well established technique for the SEM, and obtaining
crystallographic information from samples is now both routine and easy. This
online tutorial explains how an EBSD system works, describes the experiments
that can be performed and how to undertake them.
Navigation
Navigate through
the three sections of this tutorial with the link bar on the left. A
separate tutorial describes specimen preparation. Within
each section you can navigate with the second link bar you will see displayed
and with the back and next buttons at the bottom of the page.
There are many
hyperlinks in this tutorial to further information to help you understand the
basic terminology and crystallography associated with EBSD. This
information is usually displayed in a new small browser window.
Click on the
figures to bring up an enlarged view in a new browser window. In some
cases this will lead to a set of linked figures that you can move through
with the forward and back buttons provided or view in a single window. Links are also provided to
useful simulations and animations.
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