Dynamics of faceted grain boundary grooves

The dynamics of dislocation-free crystal facets is examined in the context of grain boundary grooves at the junction between two crystallites of a sol id and the liquid phase. The geometry and thermal conditions of grain bound ary grooves allow a detailed analysis of facet morphology during solidifica tion in terms of the nucleation and spreading rates of elementary crystal p lanes. Observations on the freezing of water in a two-dimensional cell reve al several dynamical features which are treated by the theory. Additional o bservations provide indications for the stiffness and premelting of grain b oundaries.