The velocity of screw dislocations in non-basal planes was measured as a function of stress and temperature in order to determine microscopic values of the activation parameters of the Friedel-Escaig mechanism. In agreement with the model, the velocity of screw dislocations was proportional to their length. The microscopic activation area was 9b2 at 300K; smaller than that deduced from macroscopic experiments, with the latter being altered by a strong variation in the density of mobile dislocations with stress. The microscopic activation energy was 0.8eV between 300 and 373K; in excellent agreement with that deduced from the Friedel-Escaig model and thus confirming the validity of that model. The energy of two isolated kinks was estimated to be more than 1.2eV; which corresponded, using elastic calculations, to a stacking-fault energy of up to 50mJ/m2, in the basal plane.

An in situ Study of Prismatic Glide in Magnesium II - Microscopic Activation Parameters. A.Couret, D.Caillard: Acta Metallurgica, 1985, 33[8], 1455-62