The University of Southampton
University of Southampton Institutional Repository

Evolution of long-period stacking ordered structure and hardness of Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy during processing by high pressure torsion

Evolution of long-period stacking ordered structure and hardness of Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy during processing by high pressure torsion
Evolution of long-period stacking ordered structure and hardness of Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy during processing by high pressure torsion
High pressure torsion (HPT) was performed at room temperature on a Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy containing long period stacking ordered (LPSO) phase with a 6.0 GPa pressure. The microstructure evolution and hardening mechanisms were analyzed. TEM shows that, with increasing HPT strain, the LPSO lamellar-shaped and block-shaped particles experience kink bending, fragmentation and dissolution; and eventually a supersaturated solid solution with nanosized grains is obtained. The decomposition of LPSO phase at room temperature is attributed to the high defect concentrations generated in the LPSO lamellae and blocks, and the Mg-rich phase. With equivalent strains increasing to ~6.6 (16 HPT revolutions), an exceptional grain refinement to 52±2 nm is achieved, and the hardness is enhanced to 128±2 HV. A quantitative model shows the hardness increase is due to the combined effects of nanosized grains, high dislocation density and dissolved alloying elements. XRD line broadening analysis, thermodynamic modelling software and elemental mapping are used to support the mechanistic interpretations.
Mg-RE alloy, long period stacking ordered phase, nanostructure, hardening mechnism, high pressure torsion
0921-5093
238-252
Sun, Wanting
67cb2890-35df-4982-adec-16c01d9b6e76
Qiao, Xiaoguang
d66f41b7-eac1-4875-8164-ee44a2a09074
Zheng, M.Y.
dd9a887e-b609-4e63-8ab1-982d5270a252
Hu, Nan
a9626677-cea5-48c7-9a7f-d3bc4116b9d5
Gao, Nong
9c1370f7-f4a9-4109-8a3a-4089b3baec21
Starink, Marco
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Sun, Wanting
67cb2890-35df-4982-adec-16c01d9b6e76
Qiao, Xiaoguang
d66f41b7-eac1-4875-8164-ee44a2a09074
Zheng, M.Y.
dd9a887e-b609-4e63-8ab1-982d5270a252
Hu, Nan
a9626677-cea5-48c7-9a7f-d3bc4116b9d5
Gao, Nong
9c1370f7-f4a9-4109-8a3a-4089b3baec21
Starink, Marco
fe61a323-4e0c-49c7-91f0-4450e1ec1e51

Sun, Wanting, Qiao, Xiaoguang, Zheng, M.Y., Hu, Nan, Gao, Nong and Starink, Marco (2018) Evolution of long-period stacking ordered structure and hardness of Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy during processing by high pressure torsion. Materials Science and Engineering: A, 738, 238-252. (doi:10.1016/j.msea.2018.09.063).

Record type: Article

Abstract

High pressure torsion (HPT) was performed at room temperature on a Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr (wt.%) alloy containing long period stacking ordered (LPSO) phase with a 6.0 GPa pressure. The microstructure evolution and hardening mechanisms were analyzed. TEM shows that, with increasing HPT strain, the LPSO lamellar-shaped and block-shaped particles experience kink bending, fragmentation and dissolution; and eventually a supersaturated solid solution with nanosized grains is obtained. The decomposition of LPSO phase at room temperature is attributed to the high defect concentrations generated in the LPSO lamellae and blocks, and the Mg-rich phase. With equivalent strains increasing to ~6.6 (16 HPT revolutions), an exceptional grain refinement to 52±2 nm is achieved, and the hardness is enhanced to 128±2 HV. A quantitative model shows the hardness increase is due to the combined effects of nanosized grains, high dislocation density and dissolved alloying elements. XRD line broadening analysis, thermodynamic modelling software and elemental mapping are used to support the mechanistic interpretations.

Text
LPSO-MSEA2018 - Accepted Manuscript
Download (3MB)

More information

Accepted/In Press date: 18 September 2018
e-pub ahead of print date: 19 September 2018
Published date: 19 December 2018
Keywords: Mg-RE alloy, long period stacking ordered phase, nanostructure, hardening mechnism, high pressure torsion

Identifiers

Local EPrints ID: 423693
URI: http://eprints.soton.ac.uk/id/eprint/423693
ISSN: 0921-5093
PURE UUID: f11220a1-298b-4775-8fad-b7f4e5f7e05e

Catalogue record

Date deposited: 27 Sep 2018 16:30
Last modified: 17 Dec 2019 05:12

Export record

Altmetrics

Contributors

Author: Wanting Sun
Author: Xiaoguang Qiao
Author: M.Y. Zheng
Author: Nan Hu
Author: Nong Gao
Author: Marco Starink

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×