Anisotropic Grain-Boundary Grooving

1. Anisotropic Grain-Boundary Grooving A vertical grain boundary intercepting a horizontal free surface forms a groove to reduce the combined surface energy of the system. The groove grows with time and is commonly used for measuring surface diffusion coefficients. We study grooving by capillarity-driven surface diffusion with strong surface energy anisotropy and finds that faceted grooves still grow with time t as t1/4. However, an anisotropic groove can be smooth if the groove surface does not cross a facet orientation. The groove has the same shape as the corresponding isotropic groove, but the growth rate is reduced by a factor that depends on the degree of anisotropy. This reduction induces an error in the surface diffusion coefficient if the isotropic model is applied to a smooth, but anisotropic groove. In Xin and Wong, we showed how to correct for this error. In Min and Wong, we extended the analysis to asymmetric surface energies and to migrating grain-boundary grooves. • Xin, T. and H. Wong "Grain-boundary grooving by surface diffusion with strong surface energy anisotropy," Acta Materialia51, 2305-2317 (2003). • Min, D. and H. Wong "Grain-boundary grooving by surface diffusion with asymmetric and strongly anisotropic surface energies," J. Applied Phys. 99, 023515 (2006). • Min, D. and H. Wong ”The effect of strong surface energy anisotropy on migrating grain-boundary grooves," J. Applied Phys. 100, 053523 (2006).