DISLOCATION MOBILITY FOR NONBASAL GLIDE IN ICE MEASURED BY INSITU X-RAY TOPOGRAPHY

Glide motion of edge dislocations in non-basal planes in ice has been observed under a compressive stress in the ⟨1100⟩ direction by X-ray topography using a high-power X-ray generator. From the observations, the dislocation velocities were determined quantitatively as a function of temperature in the range 223 to 263 K and stress in the range 0·1 to 1·4 MPa. The velocities obtained are proportional to an effective shear stress and are approximately five times larger than those for basal glide but with approximately the same activation energy of 0·6 eV. © 1990 Taylor & Francis Group, LLC.