Flow of Polycrystalline Ice at Low Stresses and Small Strains

Abstract

Tensile creep tests from −3° to −13°C at stresses between 2×105 and 2×106 dyn/cm2 with millimeter range grain-size polycrystalline ice showed that the strain rate was proportional to the stress, and that the viscosity was proportional to the grain size squared. The flow process had an apparent activation energy of 12 kcal/mol. Calculated diffusion coefficients were several orders of magnitude larger than directly measured diffusion coefficients for single crystals. Enhancement of the diffusion rate in a wide band adjacent to grain boundaries is believed to account for the observed behavior. Previously reported data for ice sintering are interpreted on the same model.