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Microstructural evolution of nanolayered Cu–Nb composites subjected to high-pressure torsion

Ekiz, E. H. and Lach, T. G. and Averback, R. S. and Mara, N. A. and Beyerlein, I. J. and Pouryazdan, M. and Hahn, H. and Bellon, P. (2014):
Microstructural evolution of nanolayered Cu–Nb composites subjected to high-pressure torsion.
In: Acta Materialia, PERGAMON-ELSEVIER SCIENCE LTD, England, pp. 178-191, 72, ISSN 13596454,
[Online-Edition: http://dx.doi.org/10.1016/j.actamat.2014.03.040],
[Article]

Abstract

Bulk nanolayered Cu/Nb composites fabricated by accumulative roll bonding (ARB), leading to a nominal layer thickness of 18 nm, were subjected to large shear deformation by high-pressure torsion at room temperature. The evolution of the microstructure was characterized using X-ray diffraction, transmission electron microscopy and atom probe tomography. At shear strains of the crystallographic texture started to change from the one stabilized by ARB, with a Kurdjumov-Sachs orientation relationship and a dominant {1 1 2}(Cu)parallel to{1 1 2}(Nb) interface plane, toward textures unlike the shear texture of monolithic Cu and Nb. At larger strains, exceeding 10, the initial layered structure was progressively replaced by a three-dimensional Cu-Nb nanocomposite. This structure remained stable with respect to grain size, morphology and global texture from strains of similar to 290 to the largest ones used in this study, 5900. The three-dimensional self-organized nanocomposites comprised biconnected Cu-rich and Nb-rich regions, with a remarkably small coexistence length scale, similar to 10 nm. The results are discussed in the context of the effect of severe plastic deformation and strain path on microstructure and texture stability in highly immiscible alloy systems. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Item Type: Article
Erschienen: 2014
Creators: Ekiz, E. H. and Lach, T. G. and Averback, R. S. and Mara, N. A. and Beyerlein, I. J. and Pouryazdan, M. and Hahn, H. and Bellon, P.
Title: Microstructural evolution of nanolayered Cu–Nb composites subjected to high-pressure torsion
Language: English
Abstract:

Bulk nanolayered Cu/Nb composites fabricated by accumulative roll bonding (ARB), leading to a nominal layer thickness of 18 nm, were subjected to large shear deformation by high-pressure torsion at room temperature. The evolution of the microstructure was characterized using X-ray diffraction, transmission electron microscopy and atom probe tomography. At shear strains of the crystallographic texture started to change from the one stabilized by ARB, with a Kurdjumov-Sachs orientation relationship and a dominant {1 1 2}(Cu)parallel to{1 1 2}(Nb) interface plane, toward textures unlike the shear texture of monolithic Cu and Nb. At larger strains, exceeding 10, the initial layered structure was progressively replaced by a three-dimensional Cu-Nb nanocomposite. This structure remained stable with respect to grain size, morphology and global texture from strains of similar to 290 to the largest ones used in this study, 5900. The three-dimensional self-organized nanocomposites comprised biconnected Cu-rich and Nb-rich regions, with a remarkably small coexistence length scale, similar to 10 nm. The results are discussed in the context of the effect of severe plastic deformation and strain path on microstructure and texture stability in highly immiscible alloy systems. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Journal or Publication Title: Acta Materialia
Volume: 72
Publisher: PERGAMON-ELSEVIER SCIENCE LTD, England
Uncontrolled Keywords: Copper alloys, Niobium alloys, Nanocomposite, High-pressure torsion, Severe plastic deformation
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 10 Feb 2016 10:05
Official URL: http://dx.doi.org/10.1016/j.actamat.2014.03.040
Identification Number: doi:10.1016/j.actamat.2014.03.040
Funders: This work was supported as part of the Center for Materials at Irradiation and Mechanical Extremes, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number 2008LANL1, APT was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT) whose local-electrode atom-probe (LEAP) tomograph was purchased and upgraded with funding from NSF-MRI (DMR-0420532) Grants., And with ONR-DURIP (N00014-0400798, N00014-0610539, N00014-0910781) Grants., Instrumentation at NUCAPT was supported by the Initiative for Sustainability and Energy at Northwestern (ISEN)., NUCAPT is a Shared Facility at the Materials Research Center of Northwestern University, supported by the National Science Foundation's MRSEC program (DMR-1121262.
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