Grain boundary grooving with simultaneous grain boundary sliding in Ni-rich NiAl Original Research Article

Thermal grooving at grain boundaries in Ni-rich NiAl was studied by atomic force microscopy technique. The determined average ratio of grain boundary to surface energy for large-angle grain boundaries at 1400°C is 0.45, which is in a good agreement with the results of computer simulations. It has been found that in most cases thermal grooving at the grain boundaries is accompanied by relative shift of the adjacent grains. This shift is associated with the grain boundary sliding caused by the relaxation of internal substructure of the specimen. A model of grain boundary grooving with the simultaneous sliding is developed. The calculated grain boundary groove profiles are in a good agreement with the experimentally measured ones.