Core energies of dislocations in bcc metals
Nicolas Bertin, Wei Cai, Sylvie Aubry, Vasily V. Bulatov
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.