FACETING TRANSFORMATION AND ENERGY OF A SIGMA-3 GRAIN-BOUNDARY IN SILVER

Grain boundary facets forming at the intersection between a grain boundary and the free surface in diffusion bonded Sigma 3[011]Ag bicrystals during prolonged annealing have been characterized crystallographically by metallographic methods. It is shown that the observed faceting has qualitatively the same character as that in Sigma 3[011] grain boundaries in Cu. The energy of an incoherent Sigma 3 grain boundary in Ag (210mJ/m(2)) is determined from the dihedral angle of the thermal groove and the extrapolated literature data on the surface tension of Ag. The facet geometry is discussed with respect to computer simulation data on the inclination dependence of the energy of Sigma 3 grain boundaries in Cu. The geometrical stability of a grain boundary near the free surface is considered.