The interactions of Shockley dislocations with stacking fault tetrahedra formed during twinning deformation in face-centred cubic crystals were studied by molecular dynamics using a copper potential. The fundamental mechanisms by which a moving Shockley dislocation interacted with a stacking fault tetrahedra involved shearing the apex, formation of a residual loop around the stacking fault tetrahedra and reactions with dislocations at the tetrahedron base. The latter reactions were critical to defect stability; they led to the formation of Shockley dislocations mobile in two faces of the parent tetrahedron making it penetrable to dislocations moving on adjacent planes during thickening of the twin. Relaxation of stacking fault tetrahedra distorted by a homogeneous twinning shear was also studied. These results revealed that parent stacking fault tetrahedra convert to structures containing rotated product stacking fault tetrahedra, rows of vacancies and stacking faults on planes bounded by partial dislocations. Dislocation mechanisms involved in Shockley and stacking fault tetrahedra interactions and formation of new defects derived from twin-sheared stacking fault tetrahedra were being analyzed.

Molecular Dynamics Studies of the Interaction of a/6〈112〉 Shockley Dislocations with Stacking Fault Tetrahedra in Copper. Part I - Intersection of SFT by an Isolated Shockley. M.Niewczas, R.G.Hoagland: Philosophical Magazine, 2009, 89[7], 623-40