Characterizing the heterogeneities of deformation in ice polycrystal
Abstract
Ice is, by itself, a heterogeneous material regarding its plastic deformation behavior. Owing to its high viscoplastic anisotropy, strong internal stress fields develop during deformation which induce localization of strain, and recrystallization processes. Our work aims at characterizing these heterogeneities through post-deformation and in-situ observations in the single- and poly-crystal. Local lattice distortions can be measured by optical automatic texture analyses, EBSD characterization down to high resolution X-ray diffraction observations of dislocation populations. In order to evaluate the heterogeneity build-up history during transient creep we apply a two-dimensional image correlation technique to display in-plane displacements. The combination of data obtained is very valuable to (a) identify areas were stress concentrates in relation to orientation neighboring, (b) where the recrystallization processes (nucleation) localize, and (c) to inferring the nature of dislocations involved during deformation. The measured heterogeneities are compared with full-field simulation of 2-D compression tests. The predicted lattice distortions compare well with the measured one. Thus, the full-field formulation appears to be a powerful predictive tool for stress and strain concentration as well as flow strength of deforming ice.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.C33A0483M
- Keywords:
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- 0738 CRYOSPHERE / Ice;
- 0798 CRYOSPHERE / Modeling;
- 3902 MINERAL PHYSICS / Creep and deformation;
- 3954 MINERAL PHYSICS / X-ray;
- neutron;
- and electron spectroscopy and diffraction