The stacking-fault energy of graphite

Abstract

Abstract Stacking-fault energies can be obtained from electron transmission micrographs by two methods. The first, due to Whelan (1958), involves measurement of the radius of curvature of a partial dislocation at an extended node. The interaction of the various partial dislocations at the measuring point is neglected and the value to be taken for the line tension of the partial dislocation is uncertain, in cases where the radius of curvature of the partial dislocations is comparable with the thickness of the foil. The second method is to measure the equilibrium separation of the partial dislocations in a long straight extended dislocation. This has the advantage that the solution of the elasticity equations is exact provided the thickness of the foil is much larger than the equilibrium separation of the partial dislocations. We have applied the second method to graphite using anisotropic elasticity.