A vertical grain boundary intercepting a horizontal free surface formed a groove to reduce the combined surface energy of the system. The groove grows with time and was commonly used for measuring surface diffusion coefficients. Grooving by capillarity-driven surface diffusion with strong surface energy anisotropy was studied here and it was found that faceted grooves still grew as t1/4. However, an anisotropic groove could be smooth if the groove surface did not cross a facet orientation. The groove had the same shape as the corresponding isotropic groove, but the growth rate was reduced by a factor that depended upon the degree of anisotropy. This reduction induced an error into the surface diffusion coefficient if the isotropic model was applied to a smooth, but anisotropic groove. It was shown how to correct for this error.

Grain-Boundary Grooving by Surface Diffusion with Strong Surface Energy Anisotropy. T.Xin, H.Wong: Acta Materialia, 2003, 51[8], 2305-17