A study was made of the effect, of an anisotropic surface free energy upon thermal grain-boundary grooving profiles under surface diffusion, by using modeling, simulations and experiments on W. Based upon Herring’s model it was shown that, when the anisotropy was slight, the groove profiles were self-similar during evolution but were often not in proportion to those which developed for isotropic material properties. The grooving kinetics obeyed power-laws, with an exponent of ¼. When the anisotropy was critical, surface-faceting occurred. When it was severe, the facets coarsened during evolution. The groove profiles which evolved under various degrees of anisotropy were observed. It was noted that the {110}- and {111}-oriented grains developed small surface facets during annealing, as in the highly anisotropic cases, while grains with no crystalline orientation tilted at about 45° to the sample surface did not.

Thermal Grain Boundary Grooving with Anisotropic Surface Free Energies. W.Zhang, P.Sachenko, I.Gladwell: Acta Materialia, 2004, 52[1], 107-16