Rheology, microstructure and crystallographic preferred orientation of matrix containing a dispersed second phase

insight from experimentally deformed ice

Daria Cyprych*, Sandra Piazolo, Christopher J L Wilson, Vladimir Luzin, David J. Prior

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We utilize in situ neutron diffraction to continuously track the average grain size and crystal preferred orientation (CPO) development in ice, during uniaxial compression of two-phase and pure ice samples. Two-phase samples are composed of ice matrix and 20 vol.% of second phases of two types: (1) rheologically soft, platy graphite, and (2) rigid, rhomb-shaped calcite. The samples were tested at 10 °C below the ice melting point, ambient pressures, and two strain rates (1×10−5 and 2.5×10−6 s−1), to 10 and 20% strain. The final CPO in the ice matrix, where second phases are present, is significantly weaker, and ice grain size is smaller than in an ice-only sample. The microstructural and rheological data point to dislocation creep as the dominant deformation regime. The evolution and final strength of the CPO in ice depend on the efficiency of the recrystallization processes, namely grain boundary migration and nucleation. These processes are markedly influenced by the strength, shape, and grain size of the second phase. In addition, CPO development in ice is further accentuated by strain partitioning into the soft second phase, and the transfer of stress onto the rigid second phase.

Original languageEnglish
Pages (from-to)272-281
Number of pages10
JournalEarth and Planetary Science Letters
Volume449
DOIs
Publication statusPublished - 1 Sep 2016

Keywords

  • ice
  • CPO
  • two phase
  • strain partitioning
  • neutron diffraction
  • uniaxial compression

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