HR: 0830h
AN: C31B-0406    [PDF]
TI: The effect of particles on dynamic recrystallization of granular ice during creep
AU: * Song, M
EM: min.song@dartmouth.edu
AF: Min Song, Ian Baker, Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 United States
AU: Baker, I
EM: ian.baker@dartmouth.edu
AF: Min Song, Ian Baker, Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 United States
AU: Cole, D M
EM: david.m.cole@erdc.usace.army.mil
AF: David M. Cole, US Army Cold Regions Research and Engineering Laboratory, Hanover, NH 03755 United States
AB: This work presents experimental observations of the influence of dispersed particles on the creep behavior and dynamic recrystallization of granular freshwater ice. The particles were present both within the grains and in the grain boundaries. The mechanical behavior of granular ice with particle contents of 0 wt.%, 0.5 wt.%, 1.0 wt.% and 4.0 wt.% was investigated under reversed direct-stress and creep loading conditions. Samples were made from laboratory-prepared freshwater ice with silt-sized particles and tested at $-12 \deg$C . Results show that creep rates of specimens with particles are higher than particle-free ice. Studies of the microstructural evolution showed that dynamic recrystallization occurs for both the particle-laden ice and particle-free ice, but that the particles enhance the recrystallization. Recrystallization nucleates along the grain boundaries in the early stage of creep straining for all specimens, but particle-laden ice shows a higher nucleation rate because the particles at the grain boundaries apparently cause an increase in strain energy during deformation. Microstructural observations also show that particles inside the grains both inhibit grain boundary migration, and act as nucleation centers for the new grains when the strain energy is high enough. The grain size of the particle-laden ice is much smaller than that of particle-free ice after a given amount of creep straining. This research was supported by NSF Office of Polar Programs, Arctic Natural Sciences Program (OPP 011737), Dr. Jane Dionne, Program Manager.
DE: 1863 Snow and ice (1827)
DE: 4540 Ice mechanics and air/sea/ice exchange processes
SC: Cryosphere [C]
MN: 2003 Fall Meeting