A comprehensive dislocation dynamics study of the strength of stacking fault tetrahedra to screw dislocation glide in Cu was presented. The methodology explicitly accounted for partial dislocation reactions in face-centred cubic crystals, which permitted the provision of more detailed insights into the dislocation-stacking fault tetrahedra processes than previous dislocation dynamics studies. The resistance due to stacking fault surfaces to dislocation cutting was computed using atomistic simulations and added in the form of a point stress to the dislocation dynamics methodology. A value of 1658.9MPa was obtained, which translated into an extra force resolved on the glide plane that dislocations must overcome before they could penetrate stacking fault tetrahedra. In fact, it was found that they did not; leading to two well differentiated regimes: (i) partial dislocation reactions, resulting in partial stacking fault tetrahedra damage, and (ii) impenetrable stacking fault tetrahedra resulting in the creation of Orowan loops. Stacking fault tetrahedra strength maps were obtained as a function of dislocation glide plane-stacking fault tetrahedra intersection height, interaction orientation, and dislocation line length. In general stacking fault tetrahedra were weaker obstacles the smaller the encountered triangular area is, which permitted the derivation of simple scaling laws with the slipped area as the only variable. These laws explained all strength curves and were used to derive a simple model of dislocation- stacking fault tetrahedra strength. The stresses required to break through obstacles in the 2.5 to 4.8nm size range were computed to be 100 to 300MPa, in good agreement with some experimental estimations and molecular dynamics calculations.

A Dislocation Dynamics Study of the Strength of Stacking Fault Tetrahedra. Part I - Interactions with Screw Dislocations. E.Martinez, J.Marian, A.Arsenlis, M.Victoria, J.M.Perlado: Philosophical Magazine, 2008, 88[6], 809-40