Imperfections in $8\mathrm{.}2$ Figure $8\mathrm{.}31$ shows a TEM image of the crystal lattice surrounding a dislocation

in NiAl. The dislocation seen in the center of the image has two separate parts as

indicated by the white arrows. Note that the plane of the picture is the plane

and that the sides of the diagram are parallel to directions of the type $.$ The

dislocation shown is a perfect dislocation with a Burgers vector which extends

from one lattice point to another. NiAl has the B$2($CsCl$)$ structure as shown in

Fig. $1\mathrm{.}5$a$.$

$($a$)$ Determine the Burgers vector and character of the dislocation shown. The$$Burgers vector should indicate not only direction but also the magnitude.$$You may call the lattice parameter for this puse.$($a$)$

$($b$)$

Figure $8\mathrm{.}31.($a$)$ A TEM image of NiAl crystal containing a dislocation $[62].$

Permission granted by M$.$ J$.$ Mills. $($b$)$ An enhanced version to simplify the Burgers

circuit analvsis.$($b$)$ Determine the Burgers tors and characters of the two separate parts of$$the dislocation indicated by the arrows