The plastic behavior of body-centered cubic (bcc) metals like tungsten is governed by the motion of 1‚ÅÑ2 <111> screw dislocations at low to medium homologous temperatures via the nucleation and propagation of kink pairs in close-packed planes. This process can be studied at the atomistic scale via molecular dynamics (MD) or density-function theory (DFT) calculations. However, these techniques would require an elevated and sometimes unaffordable computational cost to study the presence of kinks within long dislocation lines. 
In addition to the well-characterized elastic contribution, the energy of a dislocation contains an inelastic, or ‚Äòcore‚Äô, term that reflects the loss of validity of elasticity theory at dislocation segments. While the elastic part is known to be symmetric about its maximum value for the edge orientation (minimum for screw), in bcc metals, the core energy displays an asymmetry than can be characterized using atomistic calculations. In kink-pair configurations on screw dislocations, this asymmetry leads to a difference in energy between ‚Äòright‚Äô and ‚Äòleft‚Äô kinks that is not captured in elastic models. 
In this work, we calculate dislocation segment self-energies as a function of dislocation character in bcc tungsten and kink-pair enthalpies as a function of stress. To avoid finite-size artifacts in atomistic simulations, we develop continuum models of kink-pair configurations based on full elasticity and line tension approaches, parameterized with a substrate Peierls potential and dislocation self-energies obtained from atomistic calculations. The novelty of this approach also lies on including the proposed methodology to calculate dislocation core energies within the OpenKIM framework.


Predicting the kink-pair formation enthalpy for screw dislocations in tungsten via line-on-substrate and line-tension models that include core energy contributions

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