Deformation-related recrystallization processes

Drury, M. R.; Urai, János L.

doi:10.1016/0040-1951(90)90033-5

Cited by 364 publications

(212 citation statements)

References 77 publications

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“…The interior of the immature grains, labeled A and B, respectively, is of few dislocations, in contrast to nearby areas of high-density dislocations. Therefore, the classical DRX, viz., migration DRX (m-DRX) mechanism operates [24][25][26][27], which is characterized by the movement of preexisting HAGBs through the deformed microstructure, leaving a strain free region in their wake. …”

Section: Methodsmentioning

confidence: 99%

“…The average grain size was measured using the linear intercept method to be 58 nm based on statistics over 180 grains. Therefore, from these observations we can infer that the continuous, rotation DRX (r-DRX) operates [24,25,28]. This mechanism involves the gradual rotation of subgrains with increased plastic strain.…”

Section: Rotation Dynamic Recrystallization (R-drx)mentioning

confidence: 97%

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Grain refinement of pure Ti during plastic deformation

Fan

Jiang

et al. 2010

Materials Science and Engineering: A

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a b s t r a c tThe mechanism of grain refinement was studied in titanium subjected to high-rate surface mechanical attrition treatment. By cross-sectional transmission electron microscopy, the deformation structures were systematically characterized in a nanocrystalline (NC) layer of the treated surface which exhibits a grain size gradient. The microstructural evolution with increasing strain involves (1) the formation of slip bands with dislocation-free cells in their interiors, (2) nucleation and migration of high-angle grain boundaries at cell boundaries consisting of high-density tangled dislocations, leading to the formation of submicrosized grains inside the slip bands, followed by (3) the formation of subgrains and dislocation cells inside the submicrosized grains with increasing misorientations, which finally become NC grains. The mechanism of grain refinement was interpreted in terms of the classical migration dynamic recrystallization (DRX) and continuous rotation DRX, respectively, leading to submicrosized and NC grains with increasing strains at high strain rates. The cooperative grain boundary sliding is active at high strain rate, by the presence of arrays of coplanar grain boundaries.

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Section: Methodsmentioning

confidence: 99%

Section: Rotation Dynamic Recrystallization (R-drx)mentioning

confidence: 97%

Grain refinement of pure Ti during plastic deformation

Fan

Jiang

et al. 2010

Materials Science and Engineering: A

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“…Evidence for intragranular deformation by dislocation creep includes (1) phase segregation and formation of compositional layering (Kenkmann and Dresen, 2002); (2) undulose extinction of porphyroclasts; (3) a high number of low-angle (< 10 • ) misorientation angles; (4) a large number of low-angle misorientation axes with strongly clustered distributions (Fliervoet et al, 1999); and (5) misorientation axes consistent with the orientations of tilt boundaries for known slip systems in plagioclase. Furthermore, dynamic recrystallization accommodated by subgrain rotation recrystallization is inferred from microstructures such as (1) recrystallized grains lacking significant internal deformation; (2) recrystallized grains with twins oriented at a low angle to the twins in adjacent porphyroclasts; and (3) core-and-mantle structures (e.g., Drury and Urai, 1990). Recrystallization, accommodated by grain boundary migration is inferred from interpenetrating grain boundaries (Drury and Urai, 1990).…”

Section: Deformation Mechanisms In the Baja California Lithospherementioning

confidence: 99%

Constraints on the rheology of the lower crust in a strike-slip plate boundary: evidence from the San Quintín xenoliths, Baja California, Mexico

et al. 2017

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Abstract. The rheology of lower crust and its transient behavior in active strike-slip plate boundaries remain poorly understood. To address this issue, we analyzed a suite of granulite and lherzolite xenoliths from the upper Pleistocene–Holocene San Quintín volcanic field of northern Baja California, Mexico. The San Quintín volcanic field is located 20 km east of the Baja California shear zone, which accommodates the relative movement between the Pacific plate and Baja California microplate. The development of a strong foliation in both the mafic granulites and lherzolites, suggests that a lithospheric-scale shear zone exists beneath the San Quintín volcanic field. Combining microstructural observations, geothermometry, and phase equilibria modeling, we estimated that crystal-plastic deformation took place at temperatures of 750–890 °C and pressures of 400–560 MPa, corresponding to 15–22 km depth. A hot crustal geotherm of 40 ° C km−1 is required to explain the estimated deformation conditions. Infrared spectroscopy shows that plagioclase in the mafic granulites is relatively dry. Microstructures are interpreted to show that deformation in both the uppermost lower crust and upper mantle was accommodated by a combination of dislocation creep and grain-size-sensitive creep. Recrystallized grain size paleopiezometry yields low differential stresses of 12–33 and 17 MPa for plagioclase and olivine, respectively. The lower range of stresses (12–17 MPa) in the mafic granulite and lherzolite xenoliths is interpreted to be associated with transient deformation under decreasing stress conditions, following an event of stress increase. Using flow laws for dry plagioclase, we estimated a low viscosity of 1.1–1.3×1020 Pa ⋅ s for the high temperature conditions (890 °C) in the lower crust. Significantly lower viscosities in the range of 1016–1019 Pa ⋅ s, were estimated using flow laws for wet plagioclase. The shallow upper mantle has a low viscosity of 5.7×1019 Pa ⋅ s, which indicates the lack of an upper-mantle lid beneath northern Baja California. Our data show that during post-seismic transients, the upper mantle and the lower crust in the Pacific–Baja California plate boundary are characterized by similar and low differential stress. Transient viscosity of the lower crust is similar to the viscosity of the upper mantle.

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“…Only dislocations close to grain boundaries really influence boundary migration. Also, it has been observed in several systems of rock analogs that newly nucleated grains grow faster than original grains, even if the latter are barely deformed [Drury and Urai, 1990;Urai et al, 1986]. This difference may reflect differences in the organization of dislocations, in surface energy, or in the number of point defects or inclusions.…”

Section: Growthmentioning

confidence: 99%

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

Wenk¹,

Tomé²

1999

J. Geophys. Res.

100

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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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Deformation-related recrystallization processes

Cited by 364 publications

References 77 publications

Grain refinement of pure Ti during plastic deformation

Grain refinement of pure Ti during plastic deformation

Constraints on the rheology of the lower crust in a strike-slip plate boundary: evidence from the San Quintín xenoliths, Baja California, Mexico

Modeling dynamic recrystallization of olivine aggregates deformed in simple shear

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