Several interactions of screw and edge dislocations with two symmetrical tilt grain boundaries in the body-centred cubic metal tungsten were studied by atomistic simulation. Two distinct models of interatomic interactions were applied: an empirical Finnis-Sinclair potential and a bond-order potential, which was based on quantum mechanical principles within the tight-binding electronic-structure theory. The study showed that the outcome of the interactions was sensitive to the interatomic potential employed. The origins of the deviating behaviour could be traced to differences in the description of atomic bonding by the two potentials. Independent of the employed interatomic potential, the simulations reveal that simple empirical criteria for dislocation transmission, which were based on geometry and stress arguments only, do not apply in general. Instead, in most cases, processes occurring at the atomic level play a decisive role in the determination of the underlying mechanisms of dislocations/grain-boundary interactions.

Interactions between Lattice Dislocations and Twin Boundaries in Tungsten - a Comparative Atomistic Simulation Study. M.Mrovec, C.Elsässer, P.Gumbsch: Philosophical Magazine, 2009, 89[34-36], 3179-94