Dislocation density distribution at slip band-grain boundary intersections

Guo, Yi; Collins, David M.; Tarleton, Edmund; Hofmann, Felix; Wilkinson, Angus J.; Britton, T. Ben

doi:10.1016/j.actamat.2019.10.031

Cited by 87 publications

(22 citation statements)

References 58 publications

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“…In plastically deformed alloys [5], a larger number of deformation bands (DBs), that can effectively accommodate the plastic strain and give rise to the heterogeneities in microstructure, are observed and well explained in our previous work [25]. Furthermore, a higher magnitude of dislocation density is found near the grain boundaries due to the prohibition of dislocation transmission from the neighbouring grain [26,27]. Hence, both DBs and grain boundaries could be the possible nucleated sites for RX [2,18].…”

Section: Introductionsupporting

confidence: 75%

How Would the Deformation Bands Affect Recrystallization in Pure Aluminium?

Luan

Jiang

2020

SSRN Journal

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The initial grain nucleation prefers to occur inside of the DBs in the comparison with grain boundaries. DB is demonstrated to be the source of orientations and positions for the nucleated grains. The area fraction of DBs has a positive correlation with the number of nucleated grains which would contribute to the RX rate. The developed KWC phase-field model successfully calculated the kinetics of the RX process in different microstructures.

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Section: Introductionsupporting

confidence: 75%

How Would the Deformation Bands Affect Recrystallization in Pure Aluminium?

Luan

Jiang

2020

SSRN Journal

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“…These values are listed in Table 1. Despite the limitations of the technique, Guo et al (2020) showed that GND densities obtained minimizing the total line energy of the 2D lattice curvature tensor correlate well with 3D GND density measurements obtained by Differential Aperture X-ray Laue Micro-diffraction, which enables the measurement of the full (9-component) Nye lattice curvature tensor. Thus, the present method provides relative values of the GND density proportional to the misorientation whenever the latter is higher than the angular resolution of the EBSD system.…”

Section: Determination Of the Dislocation Types Composing The Subgrains Walls (Labs)mentioning

confidence: 83%

Dynamic recrystallization by subgrain rotation in olivine revealed by electron backscatter diffraction

et al. 2021

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We document how dynamic recrystallization by subgrain rotation (SGR) develops in natural olivine-rich rocks deformed in extension to up to 50% bulk finite strain (1473 K, confining pressure of 300 MPa, and stresses between 115 and 180 MPa) using electron backscatter diffraction (EBSD) mapping. SGR occurs preferentially in highly deformed grains (well-oriented to deform by dislocation glide) subjected to local stress concentrations due to interactions with hard neighboring grains (poorly-oriented olivine crystals or pyroxenes). Subgrains (misorientation <15 • ) are mainly delimited by tilt walls composed of combinations of dislocations of the [100] (001), [001](100), [100](010) and [001](010) systems, in order of decreasing frequency. The activation and prevalence of these systems agree with a Schmid factor analysis using data for high-T dislocation creep in olivine. The development of closed 3D subgrain cells by SGR recrystallization requires the contribution of at least three different slip systems, implying the activation of hard slip systems and high (local) stresses. The transition from subgrain to grain boundaries (misorientation ≥15 • ) is characterized by a sharp change in the misorientation axes that accommodate the difference in orientation between the two subgrains or grains. We propose that this change marks the creation and incorporation of new defects (grain boundary dislocations with different Burger vectors and, likely, disclinations or disconnections) at the newly-formed grain boundaries and that this might be favoured by stress concentrations due to increasing misalignment between slip systems across the boundary. Finally, we document the development of strong misorientations within the parent grains, due to the accumulation of low angle grain boundaries, and between them and the recrystallized grains. SGR recrystallization may thus produce strong dispersion of the crystal preferred orientation without the need for grain boundary sliding.

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“…Despite the limitations of the technique, Guo et al (2020) showed that GND densities obtained minimizing the total line energy of the 2D lattice curvature tensor correlate well with 3D GND density measurements obtained by Differential Aperture X-ray Laue Micro-diffraction, which enables the measurement of the full (9-component) Nye lattice curvature tensor. Thus, the present method provides relative values of the GND density proportional to the misorientation whenever the latter is higher than the angular resolution of the EBSD system.…”

Section: Determination Of the Dislocation Types Composing The Subgrains Walls (Labs)mentioning

confidence: 83%

Dynamic recrystallization by subgrain rotation in olivine revealed by electron backscatter diffraction

López-Sánchez¹,

Tommasi²,

Ismaı̈l³

et al. 2022

Preprint

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We document how dynamic recrystallization by subgrain rotation (SGR) develops in natural olivinerich rocks deformed in extension to up to 50% bulk finite strain (1473 K, confining pressure of 300 MPa, and stresses between 115 and 180 MPa) using electron backscatter diffraction (EBSD) mapping. SGR occurs preferentially in highly deformed grains (well-oriented to deform by dislocation glide) subjected to local stress concentrations due to interactions with hard neighboring grains (poorly-oriented olivine crystals or pyroxenes). Subgrains (misorientation <15°) are mainly delimited by tilt walls composed of combinations of dislocations of the [100](001), [001](100), [100](010) and [001](010) systems, in order of decreasing frequency. The activation and prevalence of these systems agree with a Schmid factor analysis using data for high-T dislocation creep in olivine. The development of closed 3D subgrain cells by SGR recrystallization requires the contribution of at least three different slip systems, implying the activation of hard slip systems and high (local) stresses. The transition from subgrain to grain boundaries (misorientation ≥15°) is characterized by a sharp change in the misorientation axes that accommodate the difference in orientation between the two subgrains or grains. We propose that this change marks the creation and incorporation of new defects (grain boundary dislocations with different Burger vectors and, likely, disclinations or disconnections) at the newly-formed grain boundaries and that this might be favoured by stress concentrations due to increasing misalignment between slip systems across the boundary. Finally, we document the development of strong misorientations within the parent grains, due to the accumulation of low angle grain boundaries, and between them and the recrystallized grains. SGR recrystallization may thus produce strong dispersion of the crystal preferred orientation without the need for grain boundary sliding.

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Dislocation density distribution at slip band-grain boundary intersections

Cited by 87 publications

References 58 publications

How Would the Deformation Bands Affect Recrystallization in Pure Aluminium?

How Would the Deformation Bands Affect Recrystallization in Pure Aluminium?

Dynamic recrystallization by subgrain rotation in olivine revealed by electron backscatter diffraction

Dynamic recrystallization by subgrain rotation in olivine revealed by electron backscatter diffraction

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