Analysis of the creep behavior of fine-grained AZ31 magnesium alloy
Analysis of the creep behavior of fine-grained AZ31 magnesium alloy
Double-shear creep testing was used to evaluate the creep behavior of a magnesium AZ31 alloy processed by equal-channel angular pressing to produce an average grain size of ~2.7 μm. The results show that rapid creep rates are observed in the early stages of deformation due to the occurrence of grain boundary sliding in the fine-grained structure but the creep rates decrease with increasing deformation due to grain growth. The stress exponent for flow in the early stages is ~2 and the activation energy is ~92 kJ mol-1 where these values are consistent with the expectations for grain boundary sliding under superplastic conditions. Annealing the material for
24 h at 723 K before creep testing produces a significantly larger grain size of ~50 μm and this prevents grain boundary sliding and leads to an increasing stress exponent at higher stresses. Deformation mechanism maps are constructed incorporating both the present experimental results for a fine-grained magnesium alloy and results from published data for the AZ31 alloy.
These maps provide a useful tool for evaluating the experimental conditions that are necessary for achieving superplastic forming operations.
AZ31 magnesium alloy, creep, deformation mechanism maps, equal-channel angular pressing, grain boundary sliding
Figueiredo, Roberto B.
cdc0ae83-425e-43ac-be02-3fb382c35981
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
10 June 2020
Figueiredo, Roberto B.
cdc0ae83-425e-43ac-be02-3fb382c35981
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Figueiredo, Roberto B. and Langdon, Terence G
(2020)
Analysis of the creep behavior of fine-grained AZ31 magnesium alloy.
Materials Science and Engineering: A, 787, [139489].
(doi:10.1016/j.msea.2020.139489).
Abstract
Double-shear creep testing was used to evaluate the creep behavior of a magnesium AZ31 alloy processed by equal-channel angular pressing to produce an average grain size of ~2.7 μm. The results show that rapid creep rates are observed in the early stages of deformation due to the occurrence of grain boundary sliding in the fine-grained structure but the creep rates decrease with increasing deformation due to grain growth. The stress exponent for flow in the early stages is ~2 and the activation energy is ~92 kJ mol-1 where these values are consistent with the expectations for grain boundary sliding under superplastic conditions. Annealing the material for
24 h at 723 K before creep testing produces a significantly larger grain size of ~50 μm and this prevents grain boundary sliding and leads to an increasing stress exponent at higher stresses. Deformation mechanism maps are constructed incorporating both the present experimental results for a fine-grained magnesium alloy and results from published data for the AZ31 alloy.
These maps provide a useful tool for evaluating the experimental conditions that are necessary for achieving superplastic forming operations.
Text
RBF-creep
- Accepted Manuscript
More information
Accepted/In Press date: 27 April 2020
e-pub ahead of print date: 4 May 2020
Published date: 10 June 2020
Additional Information:
Funding Information:
The authors acknowledge support from FAPEMIG , CAPES , CNPq and the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS .
Publisher Copyright:
© 2020 Elsevier B.V.
Keywords:
AZ31 magnesium alloy, creep, deformation mechanism maps, equal-channel angular pressing, grain boundary sliding
Identifiers
Local EPrints ID: 440989
URI: http://eprints.soton.ac.uk/id/eprint/440989
ISSN: 0921-5093
PURE UUID: 0f5a638f-d3b4-42df-9b93-fde1a575c88c
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Date deposited: 27 May 2020 16:31
Last modified: 17 Mar 2024 05:34
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Author:
Roberto B. Figueiredo
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