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Tailoring a high strength Al-4Cu alloy through processing of powders by up to 100 turns of high-pressure torsion

Tailoring a high strength Al-4Cu alloy through processing of powders by up to 100 turns of high-pressure torsion
Tailoring a high strength Al-4Cu alloy through processing of powders by up to 100 turns of high-pressure torsion
Processing by high-pressure torsion (HPT) was applied to a cold-pressed mixture of Al and Cu (4%wt) powders to successfully synthesise a high-strength nanocomposite. The powder consolidation and redistribution of second phases involved the stretching and fragmentation of the Cu domains into shorter strips and submicrometre particles. After 1 turn, the Al+4wt%Cu alloy was not fully consolidated and exhibited numerous microvoids at the disc centre. For this reason, the material displayed comparatively low microhardness at this location which triggered early metal cracking during testing through plane strain compression. An adequate consolidation was achieved after 30 HPT revolutions as the composite exhibited a homogenous distribution of Cu fragments without any visible microcavities. This is consistent with the high flow stresses achieved during plane strain compression without incipient metal cracking. At this processing stage, there is evidence of partial dissolution of Cu into the Al-Cu solid solution followed by dynamic precipitation of Al2Cu nanoprecipitates. Additional straining up to 100 turns promoted further hardening up to 270 Hv and grain refinement down to ~48 nm. However, this occurs concurrently with the coalescence and loss of coherency of the Al2Cu precipitates with the Al matrix.
aluminium alloy, consolidation of powders, dynamic precipitation, grain refinement, hardening characteristics, high-pressure torsion, Hardening characteristics, High-pressure torsion, Aluminium alloy, Dynamic precipitation, Consolidation of powders, Grain refinement
0921-5093
Haase, Olavo C.
cd2cab28-f845-4eb3-8dce-56b5d265457e
Cetlin, Paulo R.
6fe5efb8-7976-4d56-8aae-08cbf76b9628
Figueiredo, Roberto B.
330e89a5-a364-4e9a-9822-035bfd3036e2
Henrique R. Pereira, Pedro
f779d266-fbed-4143-bdeb-6807330c9a2a
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Haase, Olavo C.
cd2cab28-f845-4eb3-8dce-56b5d265457e
Cetlin, Paulo R.
6fe5efb8-7976-4d56-8aae-08cbf76b9628
Figueiredo, Roberto B.
330e89a5-a364-4e9a-9822-035bfd3036e2
Henrique R. Pereira, Pedro
f779d266-fbed-4143-bdeb-6807330c9a2a
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86

Haase, Olavo C., Cetlin, Paulo R., Figueiredo, Roberto B., Henrique R. Pereira, Pedro and Langdon, Terence G. (2023) Tailoring a high strength Al-4Cu alloy through processing of powders by up to 100 turns of high-pressure torsion. Materials Science and Engineering: A, 882, [145454]. (doi:10.1016/j.msea.2023.145454).

Record type: Article

Abstract

Processing by high-pressure torsion (HPT) was applied to a cold-pressed mixture of Al and Cu (4%wt) powders to successfully synthesise a high-strength nanocomposite. The powder consolidation and redistribution of second phases involved the stretching and fragmentation of the Cu domains into shorter strips and submicrometre particles. After 1 turn, the Al+4wt%Cu alloy was not fully consolidated and exhibited numerous microvoids at the disc centre. For this reason, the material displayed comparatively low microhardness at this location which triggered early metal cracking during testing through plane strain compression. An adequate consolidation was achieved after 30 HPT revolutions as the composite exhibited a homogenous distribution of Cu fragments without any visible microcavities. This is consistent with the high flow stresses achieved during plane strain compression without incipient metal cracking. At this processing stage, there is evidence of partial dissolution of Cu into the Al-Cu solid solution followed by dynamic precipitation of Al2Cu nanoprecipitates. Additional straining up to 100 turns promoted further hardening up to 270 Hv and grain refinement down to ~48 nm. However, this occurs concurrently with the coalescence and loss of coherency of the Al2Cu precipitates with the Al matrix.

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Accepted/In Press date: 17 July 2023
e-pub ahead of print date: 18 July 2023
Published date: 24 August 2023
Additional Information: Funding Information: The authors thank the Microscopy Centre of UFMG for the technical support during electron microscopy examination. This research was partially supported by CNPq under Grant No. 443736/2018–9 (PHRP) and FAPEMIG under Grant APQ-01342–21 (PHRP). We also thank ALTOM METALURGIA for providing the Al powders used in this study. The work of one of us was supported by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (TGL). Publisher Copyright: © 2023 Elsevier B.V.
Keywords: aluminium alloy, consolidation of powders, dynamic precipitation, grain refinement, hardening characteristics, high-pressure torsion, Hardening characteristics, High-pressure torsion, Aluminium alloy, Dynamic precipitation, Consolidation of powders, Grain refinement

Identifiers

Local EPrints ID: 482493
URI: http://eprints.soton.ac.uk/id/eprint/482493
ISSN: 0921-5093
PURE UUID: 384b9bc3-452c-465d-b70b-9ac07db34e79
ORCID for Terence G. Langdon: ORCID iD orcid.org/0000-0003-3541-9250

Catalogue record

Date deposited: 09 Oct 2023 16:47
Last modified: 06 Jun 2024 01:40

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Contributors

Author: Olavo C. Haase
Author: Paulo R. Cetlin
Author: Roberto B. Figueiredo
Author: Pedro Henrique R. Pereira

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