Misorientation

Misorientation is the difference in crystallographic orientation between two crystallites in a polycrystalline material.

In crystalline materials, the orientation of a crystallite is defined by a transformation from a sample reference frame (i.e. defined by the direction of a rolling or extrusion process and two orthogonal directions) to the local reference frame of the crystalline lattice, as defined by the basis of the unit cell. In the same way, misorientation is the transformation necessary to move from one local crystal frame to some other crystal frame. That is, it is the distance in orientation space between two distinct orientations. If the orientations are specified in terms of matrices of direction cosines g_A and g_B, then the misorientation operator ∆g_AB going from A to B can be defined as follows: