Burgers vector

Burgers vector in an edge dislocation (left) and in a screw dislocation (right). The edge dislocation can be imagined as the introduction of a half plane (gray boxes) that does not fit the crystal symmetry. The screw dislocation can be imagined as cut and shear operation along a half plane.

The direction of the vector depends on the plane of dislocation, which is usually on one of the closest-packed crystallographic planes. The magnitude is usually represented by the equation (For BCC and FCC lattices only):

Generally, the Burges vector of a dislocation is defined by performing a line integral over the distortion field around the dislocation line

In most metallic materials, the magnitude of the Burgers vector for a dislocation is of a magnitude equal to the interatomic spacing of the material, since a single dislocation will offset the crystal lattice by one close-packed crystallographic spacing unit.