And all of the four types of TSD predicted were identified. A new type of TSD, b=c+2a dislocation was identified. sense vector onto the Burgers vector, b , points to the “extra half plane” defining this edge dislocation, regardless of which way the sense vector is defined. Give the specific indices of the two {111} planes that contain the screw dislocation with the Burgers vector (2a)101 in a face-centered-cubic crystal where a is the lattice parameter of the fcc crystal. (b) Burger vector ( ) is parallel to imaginary vector ( ) in case of screw dislocation. Whereas a screw dislocation moves in a direction perpendicular to the Burgers vector and lies parallel to burger vector. Transcript. Figure 2 shows a right-handed screw dislocation with a sense vector and the corresponding Burgers vector, again using the RH/SF convention. Graphite contains varying concentrations of screw dislocations whose Burgers vector parallels the c axis. Edge and screw dislocations with line and Burgers vectors shown. Each gliding dislocation is separated into partials with Burgers vectors b=DB+BC= (D + B)+(B + C)=DC. Single crystals of natural graphite contain very few such dislocations; furthermore, their Burgers vector always exceeds 450 angstroms. It is defined to be a regularized phase gradient evaluated at the phase singularity, and is computed explicitly. (d) Imperfect basal dislocations of the Shockley partial type with Burgers vectors ACT, B