| dc.description |
The twin composition plane in graphite is a 20o tilt boundary between
lattices which are rotated, relatively, about an axis In the basal plane.
Previous work has led to the proposition that some special type of structure must
necessarily exist in the neighbourhood of the boundary which violates
normal hexagon arrangement of the carbon atoms. It is demonstrated that
tilt boundary of the required form can be explained as an array of partial
dislocations, such a boundary being possible in either the hexagonal or the
rhombohedral form. A boundary of this type is mobile, and can, by its
movement, introduce or eliminate stacking faults and thus change the volume
rhombohedral graphite present in the normal hexagonal lattice. Such
effects have been reported previously. The true twinning plane in this model is
not the composition plane, which is the plane {1101} referred to the
structural (not the morphological) axes, but the plane {1121} |
|