Twinning in graphite

A detailed investigation has been made of twins in graphite crystals. The twins are regions misoriented from the crystal by a rotation of 20° 48' about a direction in the basal plane. The twin boundaries are shown to be simple tilt boundaries of a particular angle. As well as twins, bend planes of varying angle are also observed in graphite crystals. The dislocation structure of the twin boundary is deduced and the effect of twins on the mechanical properties of graphite crystals is considered.