10:00 AM - 10:15 AM
[SCG74-05] Effect of solid particles and grain boundary on deformation of fine-grained polycrystalline ice
Keywords:ice-sheet flow, solid particle
We prepared artificial ice with and without silica-particles (particle size of 0.3 µm and dispersed-amount of 0.1wt%). Powder ice (made by spraying pure water and silica-dispersed water into liquid nitrogen) is compressed for an hour with 70 MPa pressure. Deformation experiments were conducted under constant temperature and pressure with various conditions. Our experimental results clarified the effect of solid particles as follows: 1) grain size of silica-dispersed ice is smaller than that of pure-water ice, 2) strain rate of silica-dispersed ice is larger than that of pure-water ice, 3) minimum strain rate (steady-state creep) was not achieved even with 10%-strain for both pure-water and silica-dispersed ice. Generally, a dislocation creep, which has no dependence on grain-size, dominates the ice deformation, however, our results (grain-size dependence and decreasing strain rate) suggest the possibility of grain boundary effect on the deformation mechanism.
In this presentation, we discuss the deformation mechanism of fine-grained polycrystalline ice from deformation test and microstructure analysis, and the flow of Greenland ice sheet.