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Morphological and crystallographic anisotropy of severely deformed commercially pure aluminium by three‐dimensional electron backscatter diffraction
Author(s) -
Naghdy Soroosh,
Pirgazi Hadi,
Verleysen Patricia,
Petrov Roumen,
Kestens Leo
Publication year - 2017
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576717012754
Subject(s) - electron backscatter diffraction , anisotropy , materials science , microstructure , crystallography , diffraction , shear (geology) , kikuchi line , saturation (graph theory) , aluminium , electron diffraction , composite material , optics , chemistry , physics , mathematics , reflection high energy electron diffraction , combinatorics
The aim of this paper is to examine the morphological and crystallographic anisotropy that develops during high‐pressure torsion (HPT) processing. Commercially pure aluminium was subjected to monotonic HPT deformation at room temperature. The microstructure and texture were studied by large‐area electron backscatter diffraction (EBSD) scans. Three‐dimensional EBSD scans served to scrutinize the morphological anisotropy and local texture. It was observed that two distinct stages of grain fragmentation and saturation occur during processing. Grains exhibited an ellipsoidal shape rather than an equi‐axed one. The major axes of the ellipsoids showed a favorable orientation at the steady‐state stage: an almost 20° inclination towards the shear direction. The global texture was characterized by typical shear components of face‐centered cubic metals at both stages. However, the local texture revealed a preferential fragmentation pattern in the first stage: orientations in the vicinity of ideal fibers became less heavily fragmented while non‐ideal orientations broke up more severely. This phenomenon was linked with the lattice rotation required to bring an initial orientation close to a stable one. Although the texture weakened considerably in the fragmentation stage, the texture index did not further decrease in the saturation stage. Saturation of texture, grain refinement and formation of microstructure are discussed in the light of different microstructural coarsening mechanisms.