ATOMISTIC SIMULATIONS OF [100], [110] AND [111] SYMMETRIC TILT GRAIN BOUNDARIES IN Ni3Al

The embedded atom type otentials and static relaxation method combined with the steepest descent computational technfque have been used to simulate the grain boundary atomic structures, grain boundary energies, grain boundary cohesive energies, the distribution of electron density and stress field in the rain boundar re ion, the formation energies of vacancies and other related problems of [IOO~, F1101 and f111f symmetric tilt grain boundaries with different geometrical index and composition. Their relations with the segregation of boron, behaviors of the grain boundary, and especially the stoichiometrical effect of boron induced ductility have also been studied and discussed.