Alternative transmission mode and long stacking fault formation during a dissociated screw dislocation across a coherent sliding interface

The effects of interface strength and stacking fault energy on the slip transmission of a dissociated dislocation across a coherent interface are investigated using phase field microelasticity modeling. Our results show that stress concentration by the glide dislocation leads to interface shear, which constricts and impedes the dissociated dislocation across the interface. There is a partial transmission mode where the trailing partial dislocation remains after the leading partial crosses the interface. A long stacking fault forms behind the leading partial dislocation and thus increases twinnability. A deformation map for the glide dislocation, from partial to full transmission with respect to the interface strength and the stacking fault energy for the glide plane, is constructed in good agreement with a scaling analysis.