Part I:
Analysis of Diffraction Patterns of superlattice (5 marks)
You are provided with a sketch, which locates the TEM micrographs and diffraction patterns taken of the ‘stainless steel sample’ during your lab session. (This is information that is typically recorded when carrying out TEM experiments.
• Index at least 2 of the zone axis diffraction patterns (ZAP’s) and determine the zone axis direction (ZAD) for each. (N.B. Assume the material is in fcc structure and index each ZAP and ZAD consistently.
• Plot each ZAD on a Kikuchi map. (You can use a published Kikuchi map or draw your own diagram.)
Part II:
1) Determination of Burgers Vector of Dislocations (5 marks)
• Identify the operating diffraction vector (g) for each of the images of the dislocation array taken under 2-beam diffraction conditions.
• With specific reference to these images, describe the general procedure for determining the Burgers vector (b) of the dislocations.
2) Determination chemical compositions of materials (5 marks)
• Identify the chemical composition from the EDX spectrum.
• Check the chemical composition differs from the matrix, grain boundary or any possible precipitates, if these were done by your group.
Sample Solution
