Briefly explain the origins of Kikuchi lines (see chapter 2 near end for discussion in context of a TEM diffraction pattern. Also read sections 5.6.4-5.6.6. What changes in the discussion for the OIM / EBSD context as opposed to TEM context?

Use the book attached in the following link and any other relevant source to answer the following questions.

• https://drive.google.com/file/d/1kN9QMjGsyeQXoBXHLt8kP9IwC1oswz-/view?usp=sharing

 Make your answers short and cite the source (and page number or link) of each of your answer. Kindly, we should be able to reproduce you answer from the page you cite.

5. Examine figure 2.57 in Brandon & Kaplan which shows a TEM diffraction pattern from a single grain of α-Fe (BCC Fe). Examine the apparent symmetry of the pattern (note spot diam is used to indicate the intensity of the diffracted beams) – what is the zone axis for this pattern? (hint:the diffraction pattern MUST reflect AT LEAST the symmetry of the real crystal along that direction but could appear to be higher symmetry. Index the pattern, remembering the following rules:

• The zone axis (vector that the e-beam is travelling along) points straight out of the page and is centered in the center of the pattern
• The in-plane vectors to the diffraction spots are the momentum transfer vectors and reciprocal lattice vectors ∆k=G. Since the zone axis is normal to the page and all the G vectors are in plane, the dot products of G*zone axis vector must be zero.
• The radius from pattern center to each spot is the magnitude of the G vector times a scale factor. So you can take ratios of these radii and invert them to get the ratios of d-spacings in real space.
• The d-spacing as function of hkl for a cubic crystal is equation 2.38 in B&K book.

6. Briefly explain the origins of Kikuchi lines (see chapter 2 near end for discussion in context of a TEM diffraction pattern. Also read sections 5.6.4-5.6.6. What changes in the discussion for the OIM / EBSD context as opposed to TEM context?