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The influence of strain rate and presence of dispersed second phases on the deformation behaviour of polycrystalline D2O ice
- Source :
- Journal of Glaciology, Vol 65, Pp 101-122 (2019)
- Publication Year :
- 2019
- Publisher :
- Cambridge University Press, 2019.
-
Abstract
- This contribution discusses results obtained from 3-D neutron diffraction and 2-D fabric analyser in situ deformation experiments on laboratory-prepared polycrystalline deuterated ice and ice containing a second phase. The two-phase samples used in the experiments are composed of an ice matrix with (1) air bubbles, (2) rigid, rhombohedral-shaped calcite and (3) rheologically soft, platy graphite. Samples were tested at 10°C below the melting point of deuterated ice at ambient pressures, and two strain rates of 1 × 10ā5 sā1 (fast) and 2.5 × 10ā6 sā1 (medium). Nature and distribution of the second phase controlled the rheological behaviour of the ice by pinning grain boundary migration. Peak stresses increased with the presence of second-phase particles and during fast strain rate cycles. Ice-only samples exhibit well-developed crystallographic preferred orientations (CPOs) and dynamically recrystallized microstructures, typifying deformation via dislocation creep, where the CPO intensity is influenced in part by the strain rate. CPOs are accompanied by a concentration of [c]-axes in cones about the compression axis, coinciding with increasing activity of prismatic- slip activity. Ice with second phases, deformed in a relatively slower strain rate regime, exhibit greater grain boundary migration and stronger CPO intensities than samples deformed at higher strain rates or strain rate cycles.
Details
- Language :
- English
- ISSN :
- 00221430 and 17275652
- Volume :
- 65
- Database :
- Directory of Open Access Journals
- Journal :
- Journal of Glaciology
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.19a34a989e0048958602d063aacc2c8c
- Document Type :
- article
- Full Text :
- https://doi.org/10.1017/jog.2018.100