The weak-beam method of electron microscopy was used to analyze Shockley partial dislocations in a pure hcp metal. Single crystals of cobalt were grown, oriented for basal slip and compression, and dissociation of the basal glide dislocations into partials was resolved. The arrangement of the magnetic domains did not influence the splitting-width of the partials. From a careful analysis of the observed peak separations, a room-temperature stacking-fault energy of 274mJ/m2 was deduced. The basal glide dislocations contained many jogs. The sequence of the partials was frequently reversed at a jog, leading to the conclusion that the dislocation was jogging over an odd number of lattice planes and had a stacking fault of the same intrinsic type on both sides of the jog. It was pointed out that this behavior had not been observed in the fcc structure because the reversed sequence of partials would lead to a glide dislocation containing an extrinsic fault.

Weak-Beam Study of Glide Dislocations in HCP Cobalt. A.Korner, H.P.Karnthaler: Philosophical Magazine A, 1983, 48[3], 469-77