The activation energies for plastic flow in a superplastic copper alloy
The activation energies for plastic flow in a superplastic copper alloy
A superplastic copper alloy, which is nominally single phase, exhibits a sigmoidal relationship between strain rate and stress dividing the behavior into three regions. Only a very small amount of primary creep occurs in the low stress region I and the intermediate stress region II, and temperature cycling experiments show that the activation energies are independent of the total strain within the extended steady-state region. The activation energies are ∼ 179 kJ mol−1 in region I and ∼ 144 kJ mol−1 in region II, and these values are similar to those anticipated for lattice and grain boundary diffusion, respectively. The activation energy in the high stress region III is ∼ 159 kJ mol−1, suggesting that grain boundary sliding occurs to an appreciable extent in this region in addition to an intragranular dislocation creep process.
Shei, Shen-Ann
a32f9b20-4c61-4719-a63b-d59a211b55ef
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Shei, Shen-Ann
a32f9b20-4c61-4719-a63b-d59a211b55ef
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Shei, Shen-Ann and Langdon, Terence G
(1978)
The activation energies for plastic flow in a superplastic copper alloy.
Acta Metallurgica.
(doi:10.1016/0001-6160(78)90143-8).
(In Press)
Abstract
A superplastic copper alloy, which is nominally single phase, exhibits a sigmoidal relationship between strain rate and stress dividing the behavior into three regions. Only a very small amount of primary creep occurs in the low stress region I and the intermediate stress region II, and temperature cycling experiments show that the activation energies are independent of the total strain within the extended steady-state region. The activation energies are ∼ 179 kJ mol−1 in region I and ∼ 144 kJ mol−1 in region II, and these values are similar to those anticipated for lattice and grain boundary diffusion, respectively. The activation energy in the high stress region III is ∼ 159 kJ mol−1, suggesting that grain boundary sliding occurs to an appreciable extent in this region in addition to an intragranular dislocation creep process.
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Accepted/In Press date: July 1978
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Local EPrints ID: 495574
URI: http://eprints.soton.ac.uk/id/eprint/495574
PURE UUID: bfa53833-beba-49eb-b843-63db60cd2121
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Date deposited: 18 Nov 2024 17:43
Last modified: 19 Nov 2024 02:38
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Author:
Shen-Ann Shei
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