The dislocation mechanisms which controlled individual dislocation glide on prismatic and basal planes were studied and were compared with the results of atomistic calculations. The plasticity was also studied  in situ  at an intermediate scale. The critical resolved shear stress of prismatic slip was shown to be controlled by the easy glide of dislocations on planes of high antiphase boundary energy, and the critical resolved shear stress of basal slip was shown to depend upon the collective motion of several dislocation families which formed a co-planar network. Properties such as work-hardening and ductility were explained in terms of dislocation interaction, multiplication and cross-slip. It was concluded that the high Peierls-type frictional forces were of surprisingly little importance in explaining the mechanical properties of this material.

M.Legros, A.Couret, D.Caillard: Philosophical Magazine A, 1996, 73[1], 81-99