electron backscatter diffraction (ebsd)
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ELECTRON BACKSCATTER DIFFRACTION (EBSD)
Presenter: Imtiaz AliRegistration No. : 400360
Contents
Introduction to EBSD Brief History Principal system components How the Pattern is Formed? EBSP - Electron Backscatter
Diffraction Patterns Operating conditions Uses of EBSD Summary
Introduction to EBSD
EBSD is a technique that allows: Crystallographic Orientations Misorientations Texture trends Grain size and boundary types Phases
Brief History 1928 Kikuchi lines observed in TEM 1954 Alam: patterns obtained in TEM 1973 Venebles: patterns recorded on film in SEM 1980 Patterns imaged with low light TV cameras 1990 Automatic pattern solving using Hough transform Present day
Local orientation and misorientations measurements Crystal Orientation Mapping (COM) Special grain boundaries imaged Special textures revealed Grain sizing
Principal system components
Sample tilted at 70° from the horizontal. A phosphor screen. A sensitive CCD video camera A vacuum interface for mounting the
phosphor and camera in an SEM port. Electronic hardware that controls the SEM,
including the beam position, stage, focus, and magnification.
A computer to control EBSD experiments, analyze the EBSD pattern and process and display the results.
Principal system components
How the Pattern is Formed
High energy electrons are elastically scattered by atomic planes in a crystallographic sample.
Operating conditions
Accelerating Voltage : 15-30 kV Beam current : 1-15 nA Collection angle : 70° Working distance : 10-25 mm
EBSP - Electron Backscatter Diffraction Patterns
Si single crystal As the sample is rotated, the pattern
changes to reflect the new orientaion
Uses of EBSD
Quantitative micro structural data Phase identification Strain analysis Maps
Summary EBSD has become a well established micro
structural analytical technique. EBSD mapping can be used to explore the
processing microstructure – properties relationships.
EBSD can be used on most crystalline materials
Grain size, sample tilt, and sample preparation are the primary limitations of the technique.
THANK YOU…!
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