Molecular dynamics simulations in combination with an atomistic path technique were used to examine the energies required to impinge a screw dislocation on a coherent twin boundary in Al and Cu. At large distances, it was found that the dislocation- coherent twin boundary interaction was characterized by repulsive forces which could be attributed to both the elasticity mismatch and distortion (shift and rotation) of deformation fields across the twin boundary. The repulsive forces were determined as a function of distance between the dislocation and the twin boundary based upon the molecular dynamics data and classical dislocation theory. At short distances, the interaction was significantly influenced by the shear strength of the coherent twin boundary: relatively low coherent twin boundary shear strength could induce close-range attractive forces and cause slip to be absorbed into the twin plane.

Repulsive Force between Screw Dislocation and Coherent Twin Boundary in Aluminum and Copper. Z.Chen, Z.Jin, H.Gao: Physical Review B, 2007, 75[21], 212104 (4pp)