OBSERVATION OF SLIP TRANSMISSION THROUGH A GRAIN-BOUNDARY IN ICE

In-situ X-ray topography has been used to provide the first clear demo nstration of slip transmission through a grain boundary in hexagonal i ce. Although the ice was deformed under creep conditions, the relative orientation of the grains and the orientation of the grain boundary w ith respect to the loading direction discouraged grain boundary slidin g and, thus, suppressed dislocation nucleation at the grain boundary. This particular geometrical arrangement is rarely encountered, suggest ing that slip transmission through grain boundaries in ice is a rare e vent.