Wedge dislocation as the elastic counterpart of a crystal deformation twin.

A crystal deformation twin may be visualized to form and grow the movement of partial dislocations only if the twinning dislocations especially distributed to give an invariant shear. One consequence of this requirement is that, if a critical resolved twinning stress exists in the same sense twinning as for slip, this stress depends on the reciprocal thickness of the twin. This type of model for twinning may be developed through the use of relatively unknown disclinations, in particular, the wedge dislocation.