Interactions between lattice dislocations and grain boundaries in L12 ordered compounds investigated by in situ transmission electron microscopy and computer modelling experiments

In this paper the interaction between lattice dislocations and grain boundaries in Ni3Al is reported as investigated by means of in situ transmission electron microscopy deformation experiments and modelling experiments. In particular, the interaction between screw dislocations and a coherent twin boundary was analysed in detail. The results of the in situ straining indicate that <110> screw dislocations impinging on a Σ = 3 coherent twin boundary, which have a Burgers vector parallel to the grain boundary plane, can be transmitted to the symmetric slip plane in the other grain under the influence of an applied stress. A one-to-one comparison with the results of a computer modelling study of exactly the same system in Ni3Al can be made and the experiment agrees with the simulations