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Title: Microstructure and nanohardness distribution in a polycrystalline Zn deformed by high strain rate impact

Abstract

Polycrystalline Zn with an average grain size of about 300 {mu}m was deformed by direct impact Hopkinson pressure bar at a velocity of 29 m/s. An inhomogeneous grain structure was found consisting of a center region having large average grain size of 20 {mu}m surrounded by a fine-grained rim with an average grain size of 6 {mu}m. Transmission electron microscopy investigations showed a significant dislocation density in the large-grained area while in the fine-grained rim the dislocation density was negligible. Most probably, the higher strain yielded recrystallization in the outer ring while in the center only recovery occurred. The hardening effect of dislocations overwhelms the smaller grain size strengthening in the center part resulting in higher nanohardness in this region than in the outer ring. - Graphical Abstract: (a): EBSD micrograph showing the initial microstructure of polycrystalline Zn that was subsequently submitted to high strain rate impact. (b): an inhomogeneous grain size refinement was obtained which consists of a central coarse-grained area, surrounded by a fine-grained recrystallized rim. The black arrow points to the disc center. Research Highlights: {yields} A polycrystalline Zn specimen was submitted to high strain rate impact loading. {yields} Inhomogeneous grain refinement occurred due to strain gradientmore » in impacted sample. {yields} A fine-grained recrystallized rim surrounded the coarse-grained center of specimen. {yields} The coarse-grained center exhibited higher hardness than the fine-grained rim. {yields} The higher hardness of the center was caused by the higher dislocation density.« less

Authors:
 [1];  [1];  [2]; ;  [3];  [1]
  1. LSPM, CNRS, UPR 3407, Universite Paris 13, 99 avenue Jean Baptiste Clement, 93430 Villetaeuse (France)
  2. Nexter-Munitions, 7 route de Guerry, 18023 Bourges Cedex (France)
  3. Department of Materials Physics, Eoetvoes Lorand University, Budapest, P.O.B. 32, H-1518 (Hungary)
Publication Date:
OSTI Identifier:
22066360
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 62; Journal Issue: 5; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BACKSCATTERING; DISLOCATIONS; ELECTRON DIFFRACTION; GRAIN REFINEMENT; GRAIN SIZE; HARDENING; HARDNESS; POLYCRYSTALS; RECRYSTALLIZATION; RESONANCE IONIZATION MASS SPECTROSCOPY; STRAIN RATE; STRAINS; TRANSMISSION ELECTRON MICROSCOPY; ZINC

Citation Formats

Dirras, G, Ouarem, A, Couque, H, Gubicza, J, Szommer, P, and Brinza, O. Microstructure and nanohardness distribution in a polycrystalline Zn deformed by high strain rate impact. United States: N. p., 2011. Web. doi:10.1016/J.MATCHAR.2011.03.002.
Dirras, G, Ouarem, A, Couque, H, Gubicza, J, Szommer, P, & Brinza, O. Microstructure and nanohardness distribution in a polycrystalline Zn deformed by high strain rate impact. United States. https://doi.org/10.1016/J.MATCHAR.2011.03.002
Dirras, G, Ouarem, A, Couque, H, Gubicza, J, Szommer, P, and Brinza, O. 2011. "Microstructure and nanohardness distribution in a polycrystalline Zn deformed by high strain rate impact". United States. https://doi.org/10.1016/J.MATCHAR.2011.03.002.
@article{osti_22066360,
title = {Microstructure and nanohardness distribution in a polycrystalline Zn deformed by high strain rate impact},
author = {Dirras, G and Ouarem, A and Couque, H and Gubicza, J and Szommer, P and Brinza, O},
abstractNote = {Polycrystalline Zn with an average grain size of about 300 {mu}m was deformed by direct impact Hopkinson pressure bar at a velocity of 29 m/s. An inhomogeneous grain structure was found consisting of a center region having large average grain size of 20 {mu}m surrounded by a fine-grained rim with an average grain size of 6 {mu}m. Transmission electron microscopy investigations showed a significant dislocation density in the large-grained area while in the fine-grained rim the dislocation density was negligible. Most probably, the higher strain yielded recrystallization in the outer ring while in the center only recovery occurred. The hardening effect of dislocations overwhelms the smaller grain size strengthening in the center part resulting in higher nanohardness in this region than in the outer ring. - Graphical Abstract: (a): EBSD micrograph showing the initial microstructure of polycrystalline Zn that was subsequently submitted to high strain rate impact. (b): an inhomogeneous grain size refinement was obtained which consists of a central coarse-grained area, surrounded by a fine-grained recrystallized rim. The black arrow points to the disc center. Research Highlights: {yields} A polycrystalline Zn specimen was submitted to high strain rate impact loading. {yields} Inhomogeneous grain refinement occurred due to strain gradient in impacted sample. {yields} A fine-grained recrystallized rim surrounded the coarse-grained center of specimen. {yields} The coarse-grained center exhibited higher hardness than the fine-grained rim. {yields} The higher hardness of the center was caused by the higher dislocation density.},
doi = {10.1016/J.MATCHAR.2011.03.002},
url = {https://www.osti.gov/biblio/22066360}, journal = {Materials Characterization},
issn = {1044-5803},
number = 5,
volume = 62,
place = {United States},
year = {Sun May 15 00:00:00 EDT 2011},
month = {Sun May 15 00:00:00 EDT 2011}
}