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High pressure torsion to refine grains in pure aluminum up to saturation : Mechanisms of structure evolution and their dependence on strain

Orlov, Dmitry; Kamikawa, Naoya and Tsuji, Nobuhiro (2012) In Philosophical Magazine Letters 92(18). p.2329-2350
Abstract

High-pressure torsion was used for the deformation processing of high-purity aluminum (4N-Al), while high-resolution electron-backscatter diffraction was used for the analysis of evolution of qualitative and quantitative microstructural characteristics. This study reveals a rather full picture of microstructure evolution in the high stacking fault energy fcc material and makes a continuous link between deformation microstructures at low, high and very high strains. Three stages of the microstructure evolution in 4N-Al at ambient temperature have been found: (i) the first stage in the range ∈ eq ≤ 1; (ii) a transition stage in the range 1eq ≤ 8; and (iii) a saturation stage in the range ∈ eq 8. In stages (i) and... (More)

High-pressure torsion was used for the deformation processing of high-purity aluminum (4N-Al), while high-resolution electron-backscatter diffraction was used for the analysis of evolution of qualitative and quantitative microstructural characteristics. This study reveals a rather full picture of microstructure evolution in the high stacking fault energy fcc material and makes a continuous link between deformation microstructures at low, high and very high strains. Three stages of the microstructure evolution in 4N-Al at ambient temperature have been found: (i) the first stage in the range ∈ eq ≤ 1; (ii) a transition stage in the range 1eq ≤ 8; and (iii) a saturation stage in the range ∈ eq 8. In stages (i) and (ii), grain subdivision and typical features of deformation microstructures are found. Starting from stage (ii), formation of small equiaxed (sub)grains surrounded by high-angle boundaries (HABs) is found together with minor increase in the average subgrain size. At stage (iii), recrystallized-like microstructure mostly consisting of the dynamically stable equiaxed subgrains surrounded by HABs dominates the microstructure.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
aluminum, EBSD, grain refinement, high pressure torsion, microstructure
in
Philosophical Magazine Letters
volume
92
issue
18
pages
22 pages
publisher
Taylor & Francis
external identifiers
  • scopus:84861880023
ISSN
1478-6435
DOI
10.1080/14786435.2012.671548
language
English
LU publication?
no
id
906a68d6-10f5-41a4-902c-a8332885a1b9
date added to LUP
2016-06-20 15:36:22
date last changed
2017-05-03 15:19:51
@article{906a68d6-10f5-41a4-902c-a8332885a1b9,
  abstract     = {<p>High-pressure torsion was used for the deformation processing of high-purity aluminum (4N-Al), while high-resolution electron-backscatter diffraction was used for the analysis of evolution of qualitative and quantitative microstructural characteristics. This study reveals a rather full picture of microstructure evolution in the high stacking fault energy fcc material and makes a continuous link between deformation microstructures at low, high and very high strains. Three stages of the microstructure evolution in 4N-Al at ambient temperature have been found: (i) the first stage in the range ∈ <sub>eq</sub> ≤ 1; (ii) a transition stage in the range 1eq ≤ 8; and (iii) a saturation stage in the range ∈ <sub>eq</sub> 8. In stages (i) and (ii), grain subdivision and typical features of deformation microstructures are found. Starting from stage (ii), formation of small equiaxed (sub)grains surrounded by high-angle boundaries (HABs) is found together with minor increase in the average subgrain size. At stage (iii), recrystallized-like microstructure mostly consisting of the dynamically stable equiaxed subgrains surrounded by HABs dominates the microstructure.</p>},
  author       = {Orlov, Dmitry and Kamikawa, Naoya and Tsuji, Nobuhiro},
  issn         = {1478-6435},
  keyword      = {aluminum,EBSD,grain refinement,high pressure torsion,microstructure},
  language     = {eng},
  month        = {06},
  number       = {18},
  pages        = {2329--2350},
  publisher    = {Taylor & Francis},
  series       = {Philosophical Magazine Letters},
  title        = {High pressure torsion to refine grains in pure aluminum up to saturation : Mechanisms of structure evolution and their dependence on strain},
  url          = {http://dx.doi.org/10.1080/14786435.2012.671548},
  volume       = {92},
  year         = {2012},
}