The interaction of Lomer-Cottrell locks with screw dislocations

Gunther Schoeck (1)

1 Department of Physics

In fcc crystals dislocations are dissociated into partial dislocations and therefore restricted to move on {111} glide planes. By junction reactions with dislocations on two intersecting {111} planes Lomer-Cottrell dislocations along <110> directions can be formed which are barriers for approaching screw dislocations. Treating conventionally the interaction between a dissociated screw dislocation and a LC lock using classical continuum theory assuming the partials to be Volterra dislocations leads to erroneous conclusions A realistic result can only be obtained in the framework of the Peierls model treating the partials as Peierls dislocations and taking explicitly account of the change in atomic misfit energy in the glide plane. At already moderate stresses (at less than 3 10-3 μ in Cu), the screw will combine with the LC-lock to form a Hirth-lock. As result the nature of the repulsive force will change drastically.

Mots clés: Physical Sciences

Gunther Schoeck. The interaction of Lomer-Cottrell locks with screw dislocations. Philosophical Magazine, 2010, 90 (05), pp.629-636. ⟨10.1080/14786430903193274⟩. ⟨hal-00560310⟩