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An examination of microstructural evolution in a Pb-Sn eutectic alloy processed by high-pressure torsion and subsequent self-annealing

An examination of microstructural evolution in a Pb-Sn eutectic alloy processed by high-pressure torsion and subsequent self-annealing
An examination of microstructural evolution in a Pb-Sn eutectic alloy processed by high-pressure torsion and subsequent self-annealing
The Pb-Sn alloy has a wide use in the electronic, energy storage and nuclear industries and a fine-grained Pb-Sn alloy may open up new possibilities for applications in these industries. In order to understand the behavior of grain refinement, a Pb-62% Sn eutectic alloy was processed by high-pressure torsion (HPT), stored at room temperature (RT) and then the microstructures of the alloy after HPT were repeatedly investigated during the course of self-annealing using electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is demonstrated that there is a large fraction of twin boundaries with a twin relationship of 62.8°<100> in the microstructure of the initial as-cast condition. Due to the presence of the high imposed pressure, the mobility of Ʃ21 boundaries at 71° is greatly favoured during processing by HPT. After the high pressure is removed, the mobility of dislocation-twin boundaries near 62.8°<100> is then favoured. Processing by HPT significantly increases the solubility of Sn in the Pb phase. The supersaturated state of Sn in Pb is not stable during self-annealing at RT and instead a decomposition of Sn from the Pb-rich phase is observed after storage for 16 days. The main mechanism for this decomposition is lattice diffusion.
High-pressure torsion, Pb-Sn alloy, Self-annealing, Solubility, Twin boundaries
0921-5093
Zhang, Nian X.
a70eabff-2be8-4e4e-9a2d-a1f2196bd420
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Huang, Yi
9f4df815-51c1-4ee8-ad63-a92bf997103e
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Zhang, Nian X.
a70eabff-2be8-4e4e-9a2d-a1f2196bd420
Kawasaki, Megumi
944ba471-eb78-46db-bfb7-3f0296d9ef6d
Huang, Yi
9f4df815-51c1-4ee8-ad63-a92bf997103e
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86

Zhang, Nian X., Kawasaki, Megumi, Huang, Yi and Langdon, Terence G (2021) An examination of microstructural evolution in a Pb-Sn eutectic alloy processed by high-pressure torsion and subsequent self-annealing. Materials Science and Engineering: A, 802, [140653]. (doi:10.1016/j.msea.2020.140653).

Record type: Article

Abstract

The Pb-Sn alloy has a wide use in the electronic, energy storage and nuclear industries and a fine-grained Pb-Sn alloy may open up new possibilities for applications in these industries. In order to understand the behavior of grain refinement, a Pb-62% Sn eutectic alloy was processed by high-pressure torsion (HPT), stored at room temperature (RT) and then the microstructures of the alloy after HPT were repeatedly investigated during the course of self-annealing using electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is demonstrated that there is a large fraction of twin boundaries with a twin relationship of 62.8°<100> in the microstructure of the initial as-cast condition. Due to the presence of the high imposed pressure, the mobility of Ʃ21 boundaries at 71° is greatly favoured during processing by HPT. After the high pressure is removed, the mobility of dislocation-twin boundaries near 62.8°<100> is then favoured. Processing by HPT significantly increases the solubility of Sn in the Pb phase. The supersaturated state of Sn in Pb is not stable during self-annealing at RT and instead a decomposition of Sn from the Pb-rich phase is observed after storage for 16 days. The main mechanism for this decomposition is lattice diffusion.

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NX2-PbSn-MSEA-accepted - Accepted Manuscript
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More information

Accepted/In Press date: 7 December 2020
e-pub ahead of print date: 11 December 2020
Published date: 20 January 2021
Additional Information: Funding Information: This work was supported in part by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (NXZ, YH, TGL) and in part by the National Science Foundation of the United States under grant no. DMR-1810343 (MK). Publisher Copyright: © 2020 Elsevier B.V.
Keywords: High-pressure torsion, Pb-Sn alloy, Self-annealing, Solubility, Twin boundaries

Identifiers

Local EPrints ID: 446206
URI: http://eprints.soton.ac.uk/id/eprint/446206
ISSN: 0921-5093
PURE UUID: ba672f60-908d-4a79-a243-65f66ff88641
ORCID for Yi Huang: ORCID iD orcid.org/0000-0001-9259-8123
ORCID for Terence G Langdon: ORCID iD orcid.org/0000-0003-3541-9250

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Date deposited: 28 Jan 2021 17:32
Last modified: 17 Mar 2024 06:12

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Contributors

Author: Nian X. Zhang
Author: Megumi Kawasaki
Author: Yi Huang ORCID iD

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