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Title: Determination of grain boundary mobility during recrystallization by statistical evaluation of electron backscatter diffraction measurements

Abstract

One of the key aspects influencing microstructural design pathways in metallic systems is grain boundary motion. The present work introduces a method by means of which direct measurement of grain boundary mobility vs. misorientation dependence is made possible. The technique utilizes datasets acquired by means of serial electron backscatter diffraction (EBSD) measurements. The experimental EBSD measurements are collectively analyzed, whereby datasets were used to obtain grain boundary mobility and grain aspect ratio with respect to grain boundary misorientation. The proposed method is further validated using cellular automata (CA) simulations. Single crystal aluminium was cold rolled and scratched in order to nucleate random orientations. Subsequent annealing at 300 °C resulted in grains growing, in the direction normal to the scratch, into a single deformed orientation. Growth selection was observed, wherein the boundaries with misorientations close to Σ7 CSL orientation relationship (38° 〈111〉) migrated considerably faster. The obtained boundary mobility distribution exhibited a non-monotonic behavior with a maximum corresponding to misorientation of 38° ± 2° about 〈111〉 axes ± 4°, which was 10–100 times higher than the mobility values of random high angle boundaries. Correlation with the grain aspect ratio values indicated a strong growth anisotropy displayed by the fast growing grains.more » The observations have been discussed in terms of the influence of grain boundary character on grain boundary motion during recrystallization. - Highlights: • Statistical microstructure method to measure grain boundary mobility during recrystallization • Method implementation independent of material or crystal structure • Mobility of the Σ7 boundaries in 5N Al was calculated as 4.7 × 10{sup –8} m{sup 4}/J ⋅ s. • Pronounced growth selection in the recrystallizing nuclei in Al • Boundary mobility values during recrystallization 2–3 orders of magnitude larger vis-à-vis curvature driven motion.« less

Authors:
; ; ; ;
Publication Date:
OSTI Identifier:
22587168
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 117; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; ALUMINIUM; ANISOTROPY; ANNEALING; ASPECT RATIO; BACKSCATTERING; CORRELATIONS; CRYSTAL STRUCTURE; DATASETS; ELECTRON DIFFRACTION; GRAIN BOUNDARIES; MOBILITY; MONOCRYSTALS; ORIENTATION; RANDOMNESS; RECRYSTALLIZATION

Citation Formats

Basu, I., E-mail: basu@imm.rwth-aachen.de, Chen, M., Loeck, M., Al-Samman, T., and Molodov, D.A.. Determination of grain boundary mobility during recrystallization by statistical evaluation of electron backscatter diffraction measurements. United States: N. p., 2016. Web. doi:10.1016/J.MATCHAR.2016.04.024.
Basu, I., E-mail: basu@imm.rwth-aachen.de, Chen, M., Loeck, M., Al-Samman, T., & Molodov, D.A.. Determination of grain boundary mobility during recrystallization by statistical evaluation of electron backscatter diffraction measurements. United States. doi:10.1016/J.MATCHAR.2016.04.024.
Basu, I., E-mail: basu@imm.rwth-aachen.de, Chen, M., Loeck, M., Al-Samman, T., and Molodov, D.A.. Fri . "Determination of grain boundary mobility during recrystallization by statistical evaluation of electron backscatter diffraction measurements". United States. doi:10.1016/J.MATCHAR.2016.04.024.
@article{osti_22587168,
title = {Determination of grain boundary mobility during recrystallization by statistical evaluation of electron backscatter diffraction measurements},
author = {Basu, I., E-mail: basu@imm.rwth-aachen.de and Chen, M. and Loeck, M. and Al-Samman, T. and Molodov, D.A.},
abstractNote = {One of the key aspects influencing microstructural design pathways in metallic systems is grain boundary motion. The present work introduces a method by means of which direct measurement of grain boundary mobility vs. misorientation dependence is made possible. The technique utilizes datasets acquired by means of serial electron backscatter diffraction (EBSD) measurements. The experimental EBSD measurements are collectively analyzed, whereby datasets were used to obtain grain boundary mobility and grain aspect ratio with respect to grain boundary misorientation. The proposed method is further validated using cellular automata (CA) simulations. Single crystal aluminium was cold rolled and scratched in order to nucleate random orientations. Subsequent annealing at 300 °C resulted in grains growing, in the direction normal to the scratch, into a single deformed orientation. Growth selection was observed, wherein the boundaries with misorientations close to Σ7 CSL orientation relationship (38° 〈111〉) migrated considerably faster. The obtained boundary mobility distribution exhibited a non-monotonic behavior with a maximum corresponding to misorientation of 38° ± 2° about 〈111〉 axes ± 4°, which was 10–100 times higher than the mobility values of random high angle boundaries. Correlation with the grain aspect ratio values indicated a strong growth anisotropy displayed by the fast growing grains. The observations have been discussed in terms of the influence of grain boundary character on grain boundary motion during recrystallization. - Highlights: • Statistical microstructure method to measure grain boundary mobility during recrystallization • Method implementation independent of material or crystal structure • Mobility of the Σ7 boundaries in 5N Al was calculated as 4.7 × 10{sup –8} m{sup 4}/J ⋅ s. • Pronounced growth selection in the recrystallizing nuclei in Al • Boundary mobility values during recrystallization 2–3 orders of magnitude larger vis-à-vis curvature driven motion.},
doi = {10.1016/J.MATCHAR.2016.04.024},
journal = {Materials Characterization},
number = ,
volume = 117,
place = {United States},
year = {Fri Jul 15 00:00:00 EDT 2016},
month = {Fri Jul 15 00:00:00 EDT 2016}
}