ELECTRON BACKSCATTER DIFFRACTION

1. Presenter: Imtiaz Ali
Registration No. : 400360

2.  Introduction to EBSD
 Brief History
 Principal system components
 How the Pattern is Formed?
 EBSP - Electron Backscatter Diffraction
Patterns
 Operating conditions
 Uses of EBSD
 Summary

3. EBSD is a technique that allows:
 Crystallographic Orientations
 Misorientations
 Texture trends
 Grain size and boundary types
 Phases

4.  1928 Kikuchi lines observed inTEM
 1954 Alam: patterns obtained inTEM
 1973Venebles: patterns recorded on film in SEM
 1980 Patterns imaged with low lightTV 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

5.  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.

7.  High energy electrons are elastically
scattered by atomic planes in a
crystallographic sample.

8.  Accelerating Voltage : 15-30 kV
 Beam current : 1-15 nA
 Collection angle : 70°
 Working distance : 10-25 mm

9.  Si single crystal
 As the sample is rotated, the pattern changes
to reflect the new orientaion

10.  Quantitative
 micro structural data
 Phase identification
 Strain analysis
 Maps

11.  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.