Core energies of dislocations in bcc metals

Abstract

Accurate methods and an efficient workflow for computing and documenting dislocation core energies are developed and applied to $\frac{1}{2}\ensuremath{\langle}111\ensuremath{\rangle}$ and $\ensuremath{\langle}100\ensuremath{\rangle}$ dislocations in five body-centered cubic (bcc) metals W, Ta, V, Mo, and $\ensuremath{\alpha}$-Fe represented by 13 model interatomic potentials. For each dislocation type, dislocation core energies are extracted for a large number of dislocation characters thoroughly sampling the entire 2-space of crystallographic line orientations of the bcc lattice. Of particular interest, core energies of the $\frac{1}{2}\ensuremath{\langle}111\ensuremath{\rangle}{110}$ dislocations are found to be distinctly asymmetric with respect to the sign of the character angle, whereas core energies of $\ensuremath{\langle}100\ensuremath{\rangle}{110}$ junction dislocations exhibit marked cusps for line orientations vicinal to the closed-packed $\ensuremath{\langle}111\ensuremath{\rangle}$ directions. Our findings furnish substantial insights for developing accurate models of dislocation core energies employed in mesoscale dislocation dynamics simulations of crystal plasticity.