The rigid-body displacement observed at the Σ = 5, (310)-[001] symmetric tilt grain boundary in central transition bcc metals

Abstract

Abstract The identical ∑ = 5, (310)-[001] symmetric tilt grain boundary (STGB) was fabricated in three different bcc metals (Nb, Mo and Ta) by ultrahigh-vacuum diffusion bonding and the atomic structure was observed by high-resolution transmission electron microscopy. We report the results of quantitative measures of the rigid-body shift of the ∑ = 5, (310)-[001] STGB for all three metals. The atomic structures of these boundaries were also predicted by atomistic simulations using potentials developed within the framework of the model generalized pseudopotential theory for these same three metals. These potentials are an example of a new class of interatomic potentials that incorporate angularly dependent d-state interactions. These models of interatomic interactions should have applicability to simulations of the central transition bcc metals owing to the directional nature of the d bonding. To test these new models, methods were developed for quantitative measurement of the grain-boundary structure from...