a) A stacking fault in fcc Ag is visible with Bragg reflection 220, but invisible with 202. Which of the
following is a possible displacement vector?
1. 1/3 [1 1 1]
2. -1/3 [1 1 1]
3. 1/3 [1 1 1]
b) List the other possible displacement vector (ignoring ± sign) that was not listed in a)
c) Can you identify this fault with displacement vector b) conclusively based only on the
information in a)? (If not, why not?) If not, identify a third Bragg reflection that could be used to
confirm the displacement vector that you identified in b).
d) From your TEM examination of a thin sample you observe that 8 dislocations cross a plane of
size 2µm x 2 µm. What is the approximate total dislocation line length in I cm³ of this material?
e) Are the two images below (taken with different g vectors from the same area), of precipitates or
dislocation loops? Explain your conclusion.
a
g = 110
b
g = 200
