Dynamic recrystallization during creep of single‐crystalline halite: An experimental study

Guillopé, M.; Poirier, Jean

doi:10.1029/jb084ib10p05557

Cited by 354 publications

(184 citation statements)

References 29 publications

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“…In anisotropic minerals, misorientations may be considerably larger so that some subgrains have sufficient misorientations to become active nuclei. This "subgrain rotation recrystallization" [Guillop• and Poirier, 1979;Poirier and Guillop& 1979] is equivalent to nucleation in our model, though there can be other mechanisms to create nuclei.…”

Section: Recrystallizationmentioning

confidence: 99%

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

Wenk¹,

Tomé²

1999

J. Geophys. Res.

101

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Abstract. Experiments by Zhang and Karato [1995] have shown that in simple shear dislocation creep of olivine at low strains, an asymmetric texture develops with a [100] maximum rotated away from the shear direction against the sense of shear. At large strain where recrystallization is pervasive, the texture pattern is symmetrical, and [100] is parallel to the shear direction. The deformation texture can be adequately modeled with a viscoplastic self-consistent polycrystal plasticity theory. This model can be expanded to include recrystallization, treating the process as a balance of boundary migration (growth of relatively underformed grains at the expense of highly deformed grains) and nucleation (strain-free nuclei replacing highly deformed grains). If nucleation dominates over growth, the model predicts a change from the asymmetric to the symmetric texture as recrystallization proceeds and stabilization in the "easy slip" orientation for the dominant (010)[100] slip system. This result is in accordance with the experiments and suggests that the most highly deformed orientation components dominate the recrystallization texture. The empirical model will be useful to simulate more adequately the development of anisotropy in the mantle where olivine is largely recrystallized. IntroductionSimple shear experiments of rock-forming minerals and analogs deformed by dislocation creep reveal some puzzling features. After moderate strains, the deformed original grains develop a characteristically asymmetric preferred orientation pattern with a monoclinic symmetry, including a mirror plane perpendicular to the shear plane and containing the shear direction. These experimental simple shear deformation textures (in this paper the term texture is used synonymous with lattice preferred orientation), such as those for quartz [ These orthorhombic textures cannot be predicted with polycrystal plasticity theory for deformation by dislocation glide such as Taylor, Sachs, or self-consistent models. Authors have referred to the textures as "easy slip" orientations [e.g., Schmid and Casey, 1986], implying that a microscopic slip plane of an active slip system is parallel to the macroscopic shear plane and a microscopic slip direction is parallel to the shear direction, and therefore deformation on such a slip system in simple shear is "easy." So far, there has been no explanation to how crystals rotate and remain within those orientations. Herwegh and Handy [1996] suggest a "rigid body rotation" into the easy slip orientation and an unexplained cessation of rotation once those special orientations are reached.Experimental

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Section: Recrystallizationmentioning

confidence: 99%

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

Wenk¹,

Tomé²

1999

J. Geophys. Res.

101

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“…Abundant subgrain walls, recrystallized grains of similar size as subgrains and predominantly low misorientation angles (Figs. 6e-g) suggest the activation of subgrain rotation recrystallization (e.g., Guillopé and Poirier, 1979), whereas the presence of lobate/sutured grain boundaries (Fig. 6e, f) indicates localized grain boundary migration recrystallization (Urai et al, 1986).…”

Section: Deformation Mechanisms and Fabric Evolution At The Tip Of Wementioning

confidence: 99%

Strain localization during high temperature creep of marble: The effect of inclusions

et al. 2014

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The deformation of rocks in the Earth's middle and lower crust is often localized in ductile shear zones. To better understand the initiation and propagation of high-temperature shear zones induced by the presence of structural and material heterogeneities, we performed deformation experiments in the dislocation creep regime on Carrara marble samples containing weak (limestone) or strong (novaculite) second phase inclusions. The samples were mostly deformed in torsion at a bulk shear strain rate of ≈ 1.9x10 -4 s -1 to bulk shear strains γ between 0.02 and 2.9 using a Paterson-type gas deformation apparatus at 900°C temperature and 400 MPa confining pressure. At low strain, twisted specimens with weak inclusions show minor strain hardening that is replaced by strain weakening at γ > 0.1 -0.2.Peak shear stress at the imposed conditions is about 20 MPa, which is ≈8% lower than the strength of intact samples. Strain progressively localized within the matrix with increasing bulk strain, but decayed rapidly with increasing distance from the inclusion tip.Microstructural analysis shows twinning and recrystallization within this process zone, with a strong crystallographic preferred orientation, dominated by {r} and (c) slip in .Recrystallization-induced weakening starts at local shear strain of about 1 in the process zone, corresponding to a bulk shear strain of about 0.1. In contrast, torsion of a sample containing strong inclusions deformed at similar stress as inclusion-free samples but do not show localization. The experiments demonstrate that the presence of weak heterogeneities initiates localized creep at local stress concentrations around the inclusion tips. Recrystallizationinduced grain size reduction may only locally promote grain boundary diffusion creep. Accordingly, the bulk strength of the twisted aggregate is close to or slightly below the lower (isostress) strength bound, determined from the flow strength and volume fraction of matrix and inclusions.

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“…The crystal is then replaced with a new ''strain-free'' crystal, with dislocation density r 0 = 10 10 m À2 [Montagnat and Duval, 2000]. The size of the new crystal scales with the effective stress s e 2 = s kl s kl /2 as D 0 $ s e À1.33 [Guillope and Poirier, 1979;Ross et al, 1980;Shimizu, 1998Shimizu, , 1999. A totally random orientation for the new grain is not to be expected; some subset of possible zenith angles seems more likely.…”

Section: Dynamic Recrystallizationmentioning

confidence: 99%

Fabric development with nearest‐neighbor interaction and dynamic recrystallization

Þorsteinsson

2002

J. Geophys. Res.

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[1] Polycrystals undergoing ductile deformation develop lattice-preferred orientation (fabric) as a result of intracrystalline slip. A consequence of fabric development is that bulk physical properties become anisotropic. Fabric development and macroscopic deformation are studied by examining three effects: nearest-neighbor interaction (NNI) among crystals, polygonization, and migration recrystallization. The effects of NNI are modeled by arranging the crystals on a three-dimensional cubic grid and assigning six neighbors to each crystal. The ''strength'' of interaction can vary from no interaction (homogeneous stress) to ''strong'' interaction (significant stress redistribution). Increasing the NNI leads to a more homogeneous strain. Fabric varies in both strength and symmetry at a given bulk strain, depending on the strength of NNI. For a prescribed fabric the strain rate increases as the NNI increases. Recrystallization is modeled from energy balance considerations, and polygonization is formulated in terms of stress differences. Both processes require knowledge of dislocation density, which is calculated in the model as a function of crystal strain and grain size, both of which vary with time. Models of fabric development in ice that include NNI lead to more realistic fabric evolution than models with homogeneous stress. However, available data on fabric evolution are inadequate to determine quantitatively the strength of NNI acting in ice.

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Dynamic recrystallization during creep of single‐crystalline halite: An experimental study

Cited by 354 publications

References 29 publications

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

Strain localization during high temperature creep of marble: The effect of inclusions

Fabric development with nearest‐neighbor interaction and dynamic recrystallization

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