The influence of strain rate and presence of dispersed second phases on the deformation behaviour of polycrystalline D2O ice
journal contributionposted on 09.03.2021, 01:53 by CJL Wilson, Nicholas Hunter, V Luzin, M Peternell, S Piazolo
Copyright © 2018 The Author(s). 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 × 10-5 s-1 (fast) and 2.5 × 10-6 s-1 (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.
This work was supported by the Australian Nuclear Science and Technology Organisation through projects 1702, 2178 and 2910 and undertaken at Lucas Heights, Australia. The technical support and discussions with ANSTO staff and Daria Cyprych are gratefully acknowledged. SP acknowledges support from the Australian Research Council Future Fellowship (Project FT1100070). CJLW, MP and NH acknowledge support from the bilateral DAAD-Australia-Germany Joint Research Co-operation Scheme (Project 57316937). Bill Durham and an anonymous referee made valuable comments that resulted in improvements in the paper.
JournalJournal of Glaciology
Pagination22p. (p. 101-122)
PublisherCambridge University Press
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Science & TechnologyPhysical SciencesGeography, PhysicalGeosciences, MultidisciplinaryPhysical GeographyGeologyice crystal studiesice rheologystructural glaciologyCRYSTALLOGRAPHIC PREFERRED ORIENTATIONDYNAMIC RECRYSTALLIZATIONFABRIC DEVELOPMENTPLANE-STRAINCREEP-RATEBASAL ICEBORE-HOLEWATER ICEFLOW-LAWCOREMeteorology & Atmospheric Sciences