Standard

Statistical analysis of dislocation substructure in commercially pure aluminum subjected to static and dynamic high pressure torsion. / Lanjewar, Harishchandra; Naghdy, Soroosh; Verleysen, Patricia; Kestens, Leo A.I.

In: Materials Characterization, Vol. 160, 110088, 2020.

Research output: Contribution to journalArticleScientificpeer-review

Harvard

APA

Vancouver

Author

Lanjewar, Harishchandra ; Naghdy, Soroosh ; Verleysen, Patricia ; Kestens, Leo A.I. / Statistical analysis of dislocation substructure in commercially pure aluminum subjected to static and dynamic high pressure torsion. In: Materials Characterization. 2020 ; Vol. 160.

BibTeX

@article{1f84ead4dbf4498997e28bdcea521c73,
title = "Statistical analysis of dislocation substructure in commercially pure aluminum subjected to static and dynamic high pressure torsion",
abstract = "Severe plastic deformation imposed under high hydrostatic pressure introduces a considerable dislocation substructure in metals from the early stages of deformation, ultimately resulting in grain fragmentation. Characterization and quantification of the substructure require methods with a sufficiently high angular and spatial resolution to reveal the local heterogeneities in orientation differences and the length scales of the substructure. However, the statistical relevance of the observations should be assured which requires relatively large fields of view. In present work, the evolution of dislocation substructures during static and dynamic high pressure torsion processing of commercially pure aluminum is examined. Orientation data obtained by electron backscatter diffraction using two different mapping step sizes are utilized to assess the detection of the dislocation substructures and boundaries during the grain fragmentation stage. Accumulation of distortion in the crystal produces an increase in measurement noise at each pixel which is estimated using Kamaya's plots. The storage of dislocations and related angular misfits reduces the peak height of the probability density distribution of misorientation gradients, moves the peak to higher misorientation gradients and widens the distribution. Superposition of double Rayleigh distributions over the combined dislocation boundary data predicts a slightly higher median for the frequency of geometrically necessary boundaries and larger misorientation gradients across these boundaries in dynamically deformed material. In incidental dislocation boundaries, higher misorientation gradients are only observed at lower equivalent strains. Buildup of shear strain leads to the deterioration in the quality of the fitting to a double Rayleigh distribution and is linked to the complex evolution pattern of the dislocation boundaries. Finally, in statically deformed material, anisotropy in the substructure evolution is observed in the shear and radial planes.",
keywords = "Commercial purity aluminum, Electron backscatter diffraction, Geometrically necessary dislocation density, Static and dynamic high pressure torsion, Statistical boundary analysis",
author = "Harishchandra Lanjewar and Soroosh Naghdy and Patricia Verleysen and Kestens, {Leo A.I.}",
year = "2020",
doi = "10.1016/j.matchar.2019.110088",
language = "English",
volume = "160",
journal = "Materials Characterization",
issn = "1044-5803",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Statistical analysis of dislocation substructure in commercially pure aluminum subjected to static and dynamic high pressure torsion

AU - Lanjewar, Harishchandra

AU - Naghdy, Soroosh

AU - Verleysen, Patricia

AU - Kestens, Leo A.I.

PY - 2020

Y1 - 2020

N2 - Severe plastic deformation imposed under high hydrostatic pressure introduces a considerable dislocation substructure in metals from the early stages of deformation, ultimately resulting in grain fragmentation. Characterization and quantification of the substructure require methods with a sufficiently high angular and spatial resolution to reveal the local heterogeneities in orientation differences and the length scales of the substructure. However, the statistical relevance of the observations should be assured which requires relatively large fields of view. In present work, the evolution of dislocation substructures during static and dynamic high pressure torsion processing of commercially pure aluminum is examined. Orientation data obtained by electron backscatter diffraction using two different mapping step sizes are utilized to assess the detection of the dislocation substructures and boundaries during the grain fragmentation stage. Accumulation of distortion in the crystal produces an increase in measurement noise at each pixel which is estimated using Kamaya's plots. The storage of dislocations and related angular misfits reduces the peak height of the probability density distribution of misorientation gradients, moves the peak to higher misorientation gradients and widens the distribution. Superposition of double Rayleigh distributions over the combined dislocation boundary data predicts a slightly higher median for the frequency of geometrically necessary boundaries and larger misorientation gradients across these boundaries in dynamically deformed material. In incidental dislocation boundaries, higher misorientation gradients are only observed at lower equivalent strains. Buildup of shear strain leads to the deterioration in the quality of the fitting to a double Rayleigh distribution and is linked to the complex evolution pattern of the dislocation boundaries. Finally, in statically deformed material, anisotropy in the substructure evolution is observed in the shear and radial planes.

AB - Severe plastic deformation imposed under high hydrostatic pressure introduces a considerable dislocation substructure in metals from the early stages of deformation, ultimately resulting in grain fragmentation. Characterization and quantification of the substructure require methods with a sufficiently high angular and spatial resolution to reveal the local heterogeneities in orientation differences and the length scales of the substructure. However, the statistical relevance of the observations should be assured which requires relatively large fields of view. In present work, the evolution of dislocation substructures during static and dynamic high pressure torsion processing of commercially pure aluminum is examined. Orientation data obtained by electron backscatter diffraction using two different mapping step sizes are utilized to assess the detection of the dislocation substructures and boundaries during the grain fragmentation stage. Accumulation of distortion in the crystal produces an increase in measurement noise at each pixel which is estimated using Kamaya's plots. The storage of dislocations and related angular misfits reduces the peak height of the probability density distribution of misorientation gradients, moves the peak to higher misorientation gradients and widens the distribution. Superposition of double Rayleigh distributions over the combined dislocation boundary data predicts a slightly higher median for the frequency of geometrically necessary boundaries and larger misorientation gradients across these boundaries in dynamically deformed material. In incidental dislocation boundaries, higher misorientation gradients are only observed at lower equivalent strains. Buildup of shear strain leads to the deterioration in the quality of the fitting to a double Rayleigh distribution and is linked to the complex evolution pattern of the dislocation boundaries. Finally, in statically deformed material, anisotropy in the substructure evolution is observed in the shear and radial planes.

KW - Commercial purity aluminum

KW - Electron backscatter diffraction

KW - Geometrically necessary dislocation density

KW - Static and dynamic high pressure torsion

KW - Statistical boundary analysis

UR - http://www.scopus.com/inward/record.url?scp=85077440591&partnerID=8YFLogxK

U2 - 10.1016/j.matchar.2019.110088

DO - 10.1016/j.matchar.2019.110088

M3 - Article

AN - SCOPUS:85077440591

VL - 160

JO - Materials Characterization

JF - Materials Characterization

SN - 1044-5803

M1 - 110088

ER -

ID: 68657134