Interactions between lattice dislocations and grain boundaries in Ni/sub 3/Al investigated by means of in situ TEM and computer modelling experiments. Acta Metallurgica et Materialia

The interaction of 1/2<110> screw- and 60 ° dislocations with symmetric [110] tilt boundaries was investigated by atomistic simulations using many-body potentials representing a pure f.c.c. metal and ordered intermetallic compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the structural unit model may help to predict the interaction mechanism for long period boundaries and that the interaction in ordered compounds shows similarities to the interaction in f.c.c.metals. Some comparisons with experimental observations have been made