Double kink mechanisms for discrete dislocations in BCC crystals

We present an application of the discrete dislocation theory to the characterization of the energetics of kinks in Mo, Ta and W body-centered cubic (BCC) crystals. The discrete dislocation calculations supply detailed predictions of formation and interaction energies for various double-kink formation and spreading mechanisms as a function of the geometry of the double kinks, including: the dependence of the formation energy of a double kink on its width; the energy of formation of a double kink on a screw dislocation containing a pre-existing double kink; and energyof formation of a double kink on a screw dislocation containing a pre-existing single kink. The computed interaction energies are expected to facilitates the nucleation of double kinks in close proximity to each other and to pre-existing kinks, thus promoting clustering of double kinks on screw segments and of ‘daughter’ double kinks ahead of ‘mother’ kinks. The predictions of M. P. Ariza (B) · E. Tellechea · A. S. Menguiano Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, 41092 Sevilla, Spain e-mail: [email protected] E. Tellechea e-mail: [email protected] A. S. Menguiano e-mail: [email protected] M. Ortiz Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA e-mail: [email protected] the discrete dislocation theory are found to be in good agreement with the full atomistic calculations based on empirical interatomic potentials available in the literature.