Samples were deformed to strains of up to 10% in compression at 1820 to 1920K, using constant stresses ranging from 150 to 250Mpa or a constant fixed strain rate of 5 x 10-6/s. Several types of dislocation were identified by transmission electron microscopy of the deformed crystals. Most of them had a-type Burgers vectors and were seen to glide on the basal plane or on prismatic planes. They usually appeared to be undissociated, but large dissociations were observed after long-duration deformation tests. In such cases, a-type dislocations could dissociate either by pure glide into 2 Shockley partials or by combined glide plus climb into 2 Frank-Shockley partials. In each case, the enclosed stacking fault was located on the basal plane. Dislocations of c+a-type were rarely seen. Various types of faulted loop were reported, which were delineated by Shockley, Frank or Frank-Shockley partials. The segregation of O was expected to play a role in the dissociation of dislocations.

TEM Observations of Dislocations in Aluminium Nitride after High Temperature Deformation M.Azzaz, J.P.Michel, V.Feregotto, A.George: Materials Science and Engineering B, 2000, 71[1-3], 30-8