Electron backscatter diffraction: Difference between revisions

Revision as of 20:03, 5 October 2023

Revision as of 02:49, 11 October 2023

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{{Use British English|date=March 2023}}

[[File:EBSD Si.png|thumb|An electron backscatter diffraction pattern of [[monocrystalline silicon]], taken at 20 kV with a [[Field electron emission|field-emission]] electron source|alt=An electron backscatter diffraction pattern of monocrystalline silicon, taken at 20 kV with a field-emission electron source. The Kikuchi bands intersect at the centre of the image ]]

'''Electron backscatter diffraction''' ('''EBSD''') is a [[scanning electron microscopy]] (SEM) technique used to study the [[Crystallography|crystallographic]] structure of materials. EBSD is carried out in a scanning electron microscope equipped with an EBSD detector comprising at least a [[Phosphorescence|phosphorescent]] screen, a compact lens and a low-light [[Charge-coupled device|camera]]. In this configuration, theThe SEM incident beam hits thea tilted sample. As backscattered electrons leave the sample, they interact with the crystal's periodic atomic lattice planes andthen diffractenter accordingan toimaging [[Bragg's law]] at various scattering angles before reaching the phosphor screen forming [[Kikuchi lines (physics)|Kikuchi patterns]] (EBSPs)detector. EBSDThe spatialpattern resolution dependsformed on many factors, including the nature of the material under study and the sample preparation. Thus, EBSPs can be indexed todetector provideprovides information about the material's grain [[Crystal structure|structure]], grain [[Electron crystallography|orientation]], and [[Phase (matter)|phase]] at the micro-scale. EBSD is applied for impurities and [[Crystallographic defect|defect studies]], [[Plasticity (physics)|plastic deformation]], and statistical analysis for average [[misorientation]], [[Grain boundary|grain]] size, and crystallographic texture.

EBSD canis alsoused in materials science and engineering, geology, and biological research. EBSD can be combined with [[energy-dispersive X-ray spectroscopy]] (EDS), [[cathodoluminescence]] (CL), and [[wavelength dispersive X-ray spectroscopy|wavelength-dispersive X-ray spectroscopy]] (WDS) for advanced [[Phase-change material|phase identification]] and materials discovery.

EBSD is a versatile and powerful technique that can provide valuable insights into the microstructure and properties of a wide range of materials. Hence, it is widely used in materials science and engineering, geology, and biological research. It is a key tool for developing new materials and understanding their behaviour under different conditions.

The change and degradation in electron backscatter patterns (EBSPs) provide information about [[Deformation (physics)|lattice distortion]] in the diffracting volume. Pattern degradation (i.e., diffuse quality) can be used to assess the level of plasticity. Changes in the EBSP zone axis position can be used to measure the [[residual stress]] and small lattice rotations. EBSD can also provide information about the density of [[geometrically necessary dislocations]] (GNDs). However, the lattice distortion is measured relative to a reference pattern (EBSP₀). The choice of reference pattern affects the measurement precision; e.g., a reference pattern deformed in tension will directly reduce the tensile strain magnitude derived from a high-resolution map while indirectly influencing the magnitude of other components and the spatial distribution of strain. Furthermore, the choice of EBSP₀ slightly affects the GND density distribution and magnitude.<ref name=":10" />

==Pattern formation and collection==