The thermal instability mechanism and annealed deformation behavior of Cu/Nb nanolaminate composites
The thermal instability mechanism and annealed deformation behavior of Cu/Nb nanolaminate composites
Nanoscale metallic multilayers (NMMs) have attracted significant attention owing to their enhanced mechanical properties and excellent thermal stability. However, the underlying deformation mechanisms of the high-temperature annealed microstructures have not been well clarified. In this study, the effect of annealing temperatures (500, 600, 700, 800, and 1000 °C) on the microstructural evolution and mechanical properties of Cu/Nb NMMs was investigated systematically. The results show that when the annealing temperature is lower than 800 °C the Cu/Nb NMMs maintain their initial continuous nanolayered structure. As the annealing temperature reaches 1000 °C, a thermal instability, driven by thermal grain boundary grooving and a Rayleigh instability, leads to the pinching off of the nanolayered structure and even a complete disintegration into an equiaxed grain structure. Uniaxial tensile tests show that 1000°C annealed samples exhibit an enhanced strain hardening capability compared to as-rolled NMMs and this imparts superior ultimate tensile strength (∼492 MPa) and a high elongation (∼20%). TEM observations demonstrate that high-density entangled dislocations exist in the Cu-Nb interface and layers after tensile testing of the high-temperature annealed samples. The dislocation tangles lead to stable and progressive strain hardening which is the dominant factor in determining the superior combination of strength and ductility of the high-temperature annealed samples. Thus, this study offers a promising strategy for evading the strength-ductility dilemma and instead promotes a more in-depth understanding of the deformation mechanisms of heterostructured materials.
annealing, interfaces, mechanical properties, nanoscale metallic multilayers, thermal stability, Annealing, Interfaces, Mechanical properties, Nanoscale metallic multilayers, Thermal stability
163-173
Ding, Chaogang
2edf8082-909e-4bec-a2b3-3b34943f5803
Xu, Jie
ff6d4656-c15b-45a4-bd71-d45937ec38fc
Shan, Debin
fd8652eb-1eeb-4ae2-bcc4-102320f3c2d7
Guo, Bin
ccf91dac-fef1-4f3d-be8a-9f4bfb7c2e5a
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
10 September 2023
Ding, Chaogang
2edf8082-909e-4bec-a2b3-3b34943f5803
Xu, Jie
ff6d4656-c15b-45a4-bd71-d45937ec38fc
Shan, Debin
fd8652eb-1eeb-4ae2-bcc4-102320f3c2d7
Guo, Bin
ccf91dac-fef1-4f3d-be8a-9f4bfb7c2e5a
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Ding, Chaogang, Xu, Jie, Shan, Debin, Guo, Bin and Langdon, Terence G.
(2023)
The thermal instability mechanism and annealed deformation behavior of Cu/Nb nanolaminate composites.
Journal of Materials Science and Technology, 157, .
(doi:10.1016/j.jmst.2023.01.052).
Abstract
Nanoscale metallic multilayers (NMMs) have attracted significant attention owing to their enhanced mechanical properties and excellent thermal stability. However, the underlying deformation mechanisms of the high-temperature annealed microstructures have not been well clarified. In this study, the effect of annealing temperatures (500, 600, 700, 800, and 1000 °C) on the microstructural evolution and mechanical properties of Cu/Nb NMMs was investigated systematically. The results show that when the annealing temperature is lower than 800 °C the Cu/Nb NMMs maintain their initial continuous nanolayered structure. As the annealing temperature reaches 1000 °C, a thermal instability, driven by thermal grain boundary grooving and a Rayleigh instability, leads to the pinching off of the nanolayered structure and even a complete disintegration into an equiaxed grain structure. Uniaxial tensile tests show that 1000°C annealed samples exhibit an enhanced strain hardening capability compared to as-rolled NMMs and this imparts superior ultimate tensile strength (∼492 MPa) and a high elongation (∼20%). TEM observations demonstrate that high-density entangled dislocations exist in the Cu-Nb interface and layers after tensile testing of the high-temperature annealed samples. The dislocation tangles lead to stable and progressive strain hardening which is the dominant factor in determining the superior combination of strength and ductility of the high-temperature annealed samples. Thus, this study offers a promising strategy for evading the strength-ductility dilemma and instead promotes a more in-depth understanding of the deformation mechanisms of heterostructured materials.
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Accepted/In Press date: 20 January 2023
e-pub ahead of print date: 29 March 2023
Published date: 10 September 2023
Additional Information:
Funding Information:
This work was supported by the National Natural Science Foundation of China under Grant No. 51635005 and the Program of Introducing Talents of Discipline to Universities under grant number B18017 . Partial support was provided by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (TGL).
Publisher Copyright:
© 2023
Keywords:
annealing, interfaces, mechanical properties, nanoscale metallic multilayers, thermal stability, Annealing, Interfaces, Mechanical properties, Nanoscale metallic multilayers, Thermal stability
Identifiers
Local EPrints ID: 485592
URI: http://eprints.soton.ac.uk/id/eprint/485592
ISSN: 1005-0302
PURE UUID: 780f8c2c-ce9f-41e8-ab92-f46f366393a9
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Date deposited: 12 Dec 2023 17:30
Last modified: 18 Mar 2024 02:56
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Contributors
Author:
Chaogang Ding
Author:
Jie Xu
Author:
Debin Shan
Author:
Bin Guo
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