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The Burgers vector will be the vector to complete the circuit, i.e., from the start to the end of the circuit. [2] One can also use a counterclockwise Burgers circuit from a starting point to enclose the dislocation. The Burgers vector will instead be from the end to the start of the circuit (see picture above). [3]
Lattice configuration of the slip plane in a bcc material. The arrow represents the Burgers vector in this dislocation glide system. Slip in body-centered cubic (bcc) crystals occurs along the plane of shortest Burgers vector as well; however, unlike fcc, there are no truly close-packed planes in the bcc crystal structure. Thus, a slip system ...
The yellow plane is the glide plane, the vector u represents the dislocation, b is the Burgers vector. When the dislocation moves from left to right through the crystal, the lower half of the crystal has moved one Burgers vector length to the left, relative to the upper half. Schematic representation of a screw dislocation in a crystal lattice.
A dislocation can be characterised by a vector comprising the distance and direction of relative movement it causes to atoms as it moves through the lattice. This characterising vector is called the Burgers vector and remains constant even though the shape of the dislocation may change or deform. [citation needed]
For a three dimension dislocations in a crystal, considering a region where the effects of dislocations is averaged (i.e. the crystal is large enough). The dislocations can be determined by Burgers vectors. If a Burgers circuit of the unit area normal to the unit vector has a Burgers vector
The parameter B in the above equation was derived by Cottrell and Jaswon for interaction between solute atoms and dislocations on the basis of the relative atomic size misfit ε a of solutes to be [10] = where k is the Boltzmann constant, and r 1 and r 2 are the internal and external cut-off radii of dislocation stress field.
In other cases, the dislocations may interact to form a more complex hexagonal structure. These concepts of tilt and twist boundaries represent somewhat idealized cases. The majority of boundaries are of a mixed type, containing dislocations of different types and Burgers vectors, in order to create the best fit between the neighboring grains.
A vector made from two Roman letters describes the Burgers vector of a perfect dislocation. If the vector is made from a Roman letter and a Greek letter, then it is a Frank partial if the letters are corresponding (Aα, Bβ,...) or a Shockley partial otherwise (Aβ, Aγ,...). Vectors made from two Greek letters describe stair-rod dislocations.