ENERGY AND STRUCTURAL SIMULATIONS OF THE INTERACTION BETWEEN THE GRAIN-BOUNDARY AND DISLOCATIONS IN NI3AL ALLOYS

The embedded-atom-type potentials and static relaxation method have been used to simulate the interaction between the grain boundary (GB) and dislocations in Ni3Al alloys. The focus has been placed on the energy of the interaction, the distortion of GB structural units and the dislocation core structure near the GB. The effects of various factors, such as the GB chemistry, the boron segregation and the applied stress, on the interaction have been studied and discussed. It is found that, when analysed from both an energy and a structural viewpoint, slip transfer will be facilitated by boron segregation, which is helpful for the understanding of the mechanism responsible for boron-enhanced ductility.