Symmetric tilt boundaries in body-centered cubic tantalum

Grain boundaries can play a significant role in the mechanical response of materials. Atomistic simulations are used to investigate 79 coincidence site lattice grain boundary structures and energies in tantalum, a model body-centered cubic transition metal. Quasi-symmetric Σ3, Σ5, Σ7, Σ13, and Σ27 boundaries are observed, of which Σ3 and Σ7 also exist as traditional mirror-symmetry conserving boundary structures. These results are supported by previous observations of similar phenomena in other bcc transition metal Σ5 boundaries. Metastable low energy Σ3 boundary structures in tantalum could influence the formation and stability of deformation twins and abnormal growth grain favoring Σ3 boundaries. [Display omitted]