Effect of creep parameters on the steady-state flow stress of pure metals processed by high-pressure torsion
Effect of creep parameters on the steady-state flow stress of pure metals processed by high-pressure torsion
The correlation between the flow stress and grain size for severely deformed metals remains undefined because the conventional Hall-Petch relationship ignores the expected contributions from thermally-activated phenomena in nanomaterials and also it fails to explain the reported strain softening of metals having low melting temperatures. In this study, the contribution of thermally-activated creep mechanisms to the room temperature flow stress is evaluated for 31 pure metals processed by high-pressure torsion. The steady-state grain size and the hardness of these metals are first compared to theoretical predictions from high temperature creep mechanisms. It is shown that these mechanisms are not able to predict the flow stress, although the data from metals with low melting temperatures fall close to the theoretical prediction for high-temperature grain boundary sliding suggesting a possible explanation for the unusual softening of these metals. Nevertheless, a detailed analysis demonstrates that a modified model for grain boundary sliding at low temperature provides the capability of correctly predicting the flow stresses for metals having both high and low melting temperatures. The results confirm the significance of thermally-activated phenomena in determining the flow stress of nanomaterials processed by severe plastic deformation.
Severe plastic deformation (SPD), creep, grain boundary sliding, high pressure torsion, ultrafine-grained materials, Ultrafine-grained materials, Creep, High-pressure torsion, Grain boundary sliding
Figueiredo, Roberto B.
64fe521f-9463-435f-a4a4-503c308ec82c
Edalati, Kaveh
ca70a7e0-bcb8-4a62-bddb-f7a6cbcad803
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
17 February 2022
Figueiredo, Roberto B.
64fe521f-9463-435f-a4a4-503c308ec82c
Edalati, Kaveh
ca70a7e0-bcb8-4a62-bddb-f7a6cbcad803
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Figueiredo, Roberto B., Edalati, Kaveh and Langdon, Terence G
(2022)
Effect of creep parameters on the steady-state flow stress of pure metals processed by high-pressure torsion.
Materials Science and Engineering: A, 835, [142666].
(doi:10.1016/j.msea.2022.142666).
Abstract
The correlation between the flow stress and grain size for severely deformed metals remains undefined because the conventional Hall-Petch relationship ignores the expected contributions from thermally-activated phenomena in nanomaterials and also it fails to explain the reported strain softening of metals having low melting temperatures. In this study, the contribution of thermally-activated creep mechanisms to the room temperature flow stress is evaluated for 31 pure metals processed by high-pressure torsion. The steady-state grain size and the hardness of these metals are first compared to theoretical predictions from high temperature creep mechanisms. It is shown that these mechanisms are not able to predict the flow stress, although the data from metals with low melting temperatures fall close to the theoretical prediction for high-temperature grain boundary sliding suggesting a possible explanation for the unusual softening of these metals. Nevertheless, a detailed analysis demonstrates that a modified model for grain boundary sliding at low temperature provides the capability of correctly predicting the flow stresses for metals having both high and low melting temperatures. The results confirm the significance of thermally-activated phenomena in determining the flow stress of nanomaterials processed by severe plastic deformation.
Text
Figueiredo_MSEA-2021
- Accepted Manuscript
More information
Accepted/In Press date: 10 January 2022
e-pub ahead of print date: 14 January 2022
Published date: 17 February 2022
Additional Information:
Funding Information:
RBF was supported by CNPq (grant No. 302445/2018-8 ) and FAPEMIG (grant No. TEC-PPM-00324-17 ). KE thanks Prof. Zenji Horita of Kyushu University for discussion and the MEXT , Japan, for scientific research grants 19H05176 and 21H00150 . TGL was supported by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS .
Publisher Copyright:
© 2022 Elsevier B.V.
Keywords:
Severe plastic deformation (SPD), creep, grain boundary sliding, high pressure torsion, ultrafine-grained materials, Ultrafine-grained materials, Creep, High-pressure torsion, Grain boundary sliding
Identifiers
Local EPrints ID: 454317
URI: http://eprints.soton.ac.uk/id/eprint/454317
ISSN: 0921-5093
PURE UUID: 41e3b546-5b72-4adc-842b-112027e54d99
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Date deposited: 07 Feb 2022 17:40
Last modified: 17 Mar 2024 07:03
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Author:
Roberto B. Figueiredo
Author:
Kaveh Edalati
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