Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization: insights from combined experiments and numerical simulations of polycrystalline ice

Sandra Piazolo; Maurine Montagnat; Verity Borthwick; Lynn Evans; Albert Griera; Fanny Grennerat; Herve Moulinec; John Wheeler

Abstract

We present a coupled experimental and modeling approach to better understand the role of stress field heterogeneities on deformation and post-deformational behavior in material with a high viscoplastic anisotropy e.g. polycrystalline ice. We investigate: (1) Effect of stress heterogeneities on deformation behavior and microstructural development and, (2) effect of such microstructures on post-deformational recrystallization. (1) Full-field elasto-viscoplastic modelling (CraFT) is used to predict the local stress and strain field during transient creep in a polycrystalline ice sample. Modeling input includes the experimental starting microstructure and a validated slip system dependent flow law. EBSD measurements on selected areas are used to estimate the local dislocation field utilizing the Weighted Burgers Vector (WBV) analysis. Areas of local stress concentration correlate with triple junctions and grain boundaries, originating from strain incompatibilities between differently oriented grains. In these areas, the WBV analysis shows a non-negligible c-axis component that must be related to resolved shear stress in a prismatic plane, coherent with the predicted elevated stress levels. The resultant defect structure is necessary for the formation of the observed kink bands which have a well-defined crystallographic character, lattice distortions and subgrain development. (2) The microstructures arising from (1) significantly affect post-deformational behavior. Combined post-deformational annealing experiments and numerical simulations using the microdynamic modeling platform ELLE, allow prediction of the local microstructural evolution taking recovery within grains, grain boundary migration and nucleation into account. Results from this study, can explain several of the observed features in natural ice, and help to refine large scale models.

Original language	English
Pages	1
Number of pages	1
Publication status	Published - 2014
Event	American Geophysical Union Fall Meeting - San Francisco Duration: 15 Dec 2014 → 19 Dec 2014

Conference

Conference	American Geophysical Union Fall Meeting
City	San Francisco
Period	15/12/14 → 19/12/14

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Piazolo, S., Montagnat, M., Borthwick, V., Evans, L., Griera, A., Grennerat, F., Moulinec, H., & Wheeler, J. (2014). Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization: insights from combined experiments and numerical simulations of polycrystalline ice. 1. Abstract from American Geophysical Union Fall Meeting, San Francisco.

@conference{7cf9b55054db4d4baeac4f976a5947d1,

title = "Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization: insights from combined experiments and numerical simulations of polycrystalline ice",

abstract = "We present a coupled experimental and modeling approach to better understand the role of stress field heterogeneities on deformation and post-deformational behavior in material with a high viscoplastic anisotropy e.g. polycrystalline ice. We investigate: (1) Effect of stress heterogeneities on deformation behavior and microstructural development and, (2) effect of such microstructures on post-deformational recrystallization. (1) Full-field elasto-viscoplastic modelling (CraFT) is used to predict the local stress and strain field during transient creep in a polycrystalline ice sample. Modeling input includes the experimental starting microstructure and a validated slip system dependent flow law. EBSD measurements on selected areas are used to estimate the local dislocation field utilizing the Weighted Burgers Vector (WBV) analysis. Areas of local stress concentration correlate with triple junctions and grain boundaries, originating from strain incompatibilities between differently oriented grains. In these areas, the WBV analysis shows a non-negligible c-axis component that must be related to resolved shear stress in a prismatic plane, coherent with the predicted elevated stress levels. The resultant defect structure is necessary for the formation of the observed kink bands which have a well-defined crystallographic character, lattice distortions and subgrain development. (2) The microstructures arising from (1) significantly affect post-deformational behavior. Combined post-deformational annealing experiments and numerical simulations using the microdynamic modeling platform ELLE, allow prediction of the local microstructural evolution taking recovery within grains, grain boundary migration and nucleation into account. Results from this study, can explain several of the observed features in natural ice, and help to refine large scale models.",

author = "Sandra Piazolo and Maurine Montagnat and Verity Borthwick and Lynn Evans and Albert Griera and Fanny Grennerat and Herve Moulinec and John Wheeler",

year = "2014",

language = "English",

pages = "1",

note = "American Geophysical Union Fall Meeting ; Conference date: 15-12-2014 Through 19-12-2014",

}

Piazolo, S, Montagnat, M, Borthwick, V, Evans, L, Griera, A, Grennerat, F, Moulinec, H & Wheeler, J 2014, 'Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization: insights from combined experiments and numerical simulations of polycrystalline ice', American Geophysical Union Fall Meeting, San Francisco, 15/12/14 - 19/12/14 pp. 1.

Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization: insights from combined experiments and numerical simulations of polycrystalline ice. / Piazolo, Sandra; Montagnat, Maurine; Borthwick, Verity et al.
2014. 1 Abstract from American Geophysical Union Fall Meeting, San Francisco.

Research output: Contribution to conference › Abstract

TY - CONF

T1 - Stress heterogeneities in anisotropic materials - their effect on dislocation fields and post-deformational recrystallization

T2 - American Geophysical Union Fall Meeting

AU - Piazolo, Sandra

AU - Montagnat, Maurine

AU - Borthwick, Verity

AU - Evans, Lynn

AU - Griera, Albert

AU - Grennerat, Fanny

AU - Moulinec, Herve

AU - Wheeler, John

PY - 2014

Y1 - 2014

N2 - We present a coupled experimental and modeling approach to better understand the role of stress field heterogeneities on deformation and post-deformational behavior in material with a high viscoplastic anisotropy e.g. polycrystalline ice. We investigate: (1) Effect of stress heterogeneities on deformation behavior and microstructural development and, (2) effect of such microstructures on post-deformational recrystallization. (1) Full-field elasto-viscoplastic modelling (CraFT) is used to predict the local stress and strain field during transient creep in a polycrystalline ice sample. Modeling input includes the experimental starting microstructure and a validated slip system dependent flow law. EBSD measurements on selected areas are used to estimate the local dislocation field utilizing the Weighted Burgers Vector (WBV) analysis. Areas of local stress concentration correlate with triple junctions and grain boundaries, originating from strain incompatibilities between differently oriented grains. In these areas, the WBV analysis shows a non-negligible c-axis component that must be related to resolved shear stress in a prismatic plane, coherent with the predicted elevated stress levels. The resultant defect structure is necessary for the formation of the observed kink bands which have a well-defined crystallographic character, lattice distortions and subgrain development. (2) The microstructures arising from (1) significantly affect post-deformational behavior. Combined post-deformational annealing experiments and numerical simulations using the microdynamic modeling platform ELLE, allow prediction of the local microstructural evolution taking recovery within grains, grain boundary migration and nucleation into account. Results from this study, can explain several of the observed features in natural ice, and help to refine large scale models.

AB - We present a coupled experimental and modeling approach to better understand the role of stress field heterogeneities on deformation and post-deformational behavior in material with a high viscoplastic anisotropy e.g. polycrystalline ice. We investigate: (1) Effect of stress heterogeneities on deformation behavior and microstructural development and, (2) effect of such microstructures on post-deformational recrystallization. (1) Full-field elasto-viscoplastic modelling (CraFT) is used to predict the local stress and strain field during transient creep in a polycrystalline ice sample. Modeling input includes the experimental starting microstructure and a validated slip system dependent flow law. EBSD measurements on selected areas are used to estimate the local dislocation field utilizing the Weighted Burgers Vector (WBV) analysis. Areas of local stress concentration correlate with triple junctions and grain boundaries, originating from strain incompatibilities between differently oriented grains. In these areas, the WBV analysis shows a non-negligible c-axis component that must be related to resolved shear stress in a prismatic plane, coherent with the predicted elevated stress levels. The resultant defect structure is necessary for the formation of the observed kink bands which have a well-defined crystallographic character, lattice distortions and subgrain development. (2) The microstructures arising from (1) significantly affect post-deformational behavior. Combined post-deformational annealing experiments and numerical simulations using the microdynamic modeling platform ELLE, allow prediction of the local microstructural evolution taking recovery within grains, grain boundary migration and nucleation into account. Results from this study, can explain several of the observed features in natural ice, and help to refine large scale models.

M3 - Abstract

SP - 1

Y2 - 15 December 2014 through 19 December 2014

ER -