Application of diffraction
Diffraction in metals and alloys: diffraction conditions

Electron microscopy enables a variety of diffraction modes, not forgetting reflection and backscatter diffraction patterns. These techniques will be discussed in a future issue.

These include area-selective diffraction, microdiffraction and convergent beam techniques (the incident beam has a large aperture, whereas in the previous methods, the incident beam is almost parallel, i.e. hardly convergent).

• The convergent beam method highlights Laue zones, i.e. several successive planes of the reciprocal lattice, providing important information on lattice symmetries and type.

  The simulation in figure 20, carried out with JEMS, shows the three Laue zones, 0, 1 and 2, giving three-dimensional information on the reciprocal network.

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