© Oxford Instruments Analytical Limited 2001

MODULE 4 - Introduction to EBSD

• Crystallographic Orientations

• Misorientations

• Texture trends• Grain size and boundary types

• Phases

EBSD = Electron Backscatter Diffraction

EBSD is a technique that allows:

To be characterised and quantified on a sub-micron scale

© Oxford Instruments Analytical Limited 2001

Introduction to EBSD - 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 misorientation measurements – Crystal Orientation Mapping (COM)– Special grain boundaries imaged– Special textures revealed – Grain sizing

© Oxford Instruments Analytical Limited 2001

Introduction to EBSD - Hardware

• Schematic layout of components

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Introduction to EBSD - Collection Geometry

• 70.5 deg tilt

• Approx. 70 steradian of pattern detected

• Distances shown are arbitrary

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Introduction to EBSD - Forward Scattered Electron Imaging (FSE)

• FSE greatly enhances diffraction contrast in imaging

• Grains and grain boundaries are clearly revealed

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Introduction to EBSD - FSE Examples

• Nickel

• Austenitic Stainless Steel

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Introduction to EBSD - Crystal Orientation Mapping (COM)

• Crystal uses reference electron image• Orientation obtained at every pixel• Color derived from inverse Pole Figure

color key• Hough transform for every pixel stored

for post acquistion reprocessing

© Oxford Instruments Analytical Limited 2001

Introduction to EBSD - Color Key for COMs

• COM with Inverse Pole Figure color key for cubic material

• Red = 100• Green = 110• Blue = 111

planes parallel to the surface