Thermal grooving at grain boundaries in Ni-rich specimens was studied by using atomic force microscopic techniques. The average ratio of grain-boundary to surface energy for large-angle grain boundaries at 1400C was 0.45. This value supported the results of computer simulations. It was found that, in most cases, thermal grooving at the grain boundaries was associated with a relative shift of the adjacent grains. This shift was related to grain-boundary sliding which was caused by the relaxation of the internal sub-structure of the specimen. A model of grain-boundary grooving, with simultaneous sliding, was developed. The calculated grain-boundary groove profiles were in a good agreement with experimentally measured ones.

Grain Boundary Grooving with Simultaneous Grain Boundary Sliding in Ni-rich NiAl. E.Rabkin, L.Klinger, T.Izyumova, A.Berner, Y.Semenov: Acta Materialia, 2001, 49[8], 1429-38