Atomic structure of the Σ5 (310)/[001] symmetric tilt grain boundary in tantalum

The high resolution images of the Σ5 (310)/[001] symmetric tilt grain boundary (STGB) in Ta show that the grain boundary contains a rigid body shift of the crystals along [001]. The magnitude of the shift varies slightly along the length of the image but the average value (0.055 nm = 0.17 a0) is in good agreement with the shift predicted by the atomistic simulations. The results of the study on Ta, when combined with previously reported and similarly successful results on Nb and MO, demonstrate the sensitivity of GB structures to the non-central nature of bonding in these BCC transition metals, as embodied in the MGPT potentials.