The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy

The body-centered cubic (BCC)-structured magnesium–lithium (Mg-Li) alloy is the lightest metal material, but its mechanical properties are poor, especially its strength. In this study, the effect of adding rare earth Y on the microstructure and mechanical properties of as-cast BCC Mg-11Li-6Zn-xY (x...

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Main Authors: Honghui Lin, Xuetao Ke, Guangxin Xiong, Binqing Shi, Zhengrong Zhang, Chuanqiang Li
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/3/321
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author Honghui Lin
Xuetao Ke
Guangxin Xiong
Binqing Shi
Zhengrong Zhang
Chuanqiang Li
author_facet Honghui Lin
Xuetao Ke
Guangxin Xiong
Binqing Shi
Zhengrong Zhang
Chuanqiang Li
author_sort Honghui Lin
collection DOAJ
description The body-centered cubic (BCC)-structured magnesium–lithium (Mg-Li) alloy is the lightest metal material, but its mechanical properties are poor, especially its strength. In this study, the effect of adding rare earth Y on the microstructure and mechanical properties of as-cast BCC Mg-11Li-6Zn-xY (x = 0, 0.5, 1.2, and 2, in wt.%) alloys was investigated. The results revealed that massive amounts of nano-scale θ (MgLiZn) and/or θ’ (MgLi<sub>2</sub>Zn) precipitated inside the grains, and some θ phases precipitated at the grain boundaries in the Mg-11Li-6Zn alloy. With the addition of Y, W phases formed at the grain boundary, their content gradually increased with the Y concentration, and the grain size decreased simultaneously. The Mg-11Li-6Zn-0.5Y alloy exhibited higher ultimate tensile strength (190 MPa) and elongation (27%) at room temperature than those (170 MPa and 22%) of the Mg-11Li-6Zn alloy, presenting improvements of 11.8% and 22.7% in strength and ductility, respectively. The improvements in the mechanical properties of the Mg-11Li-6Zn alloy achieved by adding less Y could be attributed to the formation of moderate W phases and a reduction in grain size. However, once the addition of Y became excessive, the mechanical properties of the Mg-11Li-6Zn-1.2Y alloy were reduced due to the formation of too many reticular W phases. In addition, the Mg-11Li-6Zn-2Y alloy containing the highest Y content had the lowest ultimate tensile strength, 163 MPa, and highest ductility, 38%, due to the combined effect of the most reticular W phases and the smallest grains. Furthermore, the fracture morphology of the Mg-11Li-6Zn alloy displayed apparent necking, which became insignificant after the addition of Y, indicating that this addition could improve its uniform plastic deformation ability.
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spelling doaj-art-7837a4abb6e24904aa97b43ff9004cc02025-08-20T01:49:01ZengMDPI AGMetals2075-47012025-03-0115332110.3390/met15030321The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn AlloyHonghui Lin0Xuetao Ke1Guangxin Xiong2Binqing Shi3Zhengrong Zhang4Chuanqiang Li5School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Materials and Energy, Foshan University, Foshan 528000, ChinaSchool of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, ChinaSchool of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, ChinaThe body-centered cubic (BCC)-structured magnesium–lithium (Mg-Li) alloy is the lightest metal material, but its mechanical properties are poor, especially its strength. In this study, the effect of adding rare earth Y on the microstructure and mechanical properties of as-cast BCC Mg-11Li-6Zn-xY (x = 0, 0.5, 1.2, and 2, in wt.%) alloys was investigated. The results revealed that massive amounts of nano-scale θ (MgLiZn) and/or θ’ (MgLi<sub>2</sub>Zn) precipitated inside the grains, and some θ phases precipitated at the grain boundaries in the Mg-11Li-6Zn alloy. With the addition of Y, W phases formed at the grain boundary, their content gradually increased with the Y concentration, and the grain size decreased simultaneously. The Mg-11Li-6Zn-0.5Y alloy exhibited higher ultimate tensile strength (190 MPa) and elongation (27%) at room temperature than those (170 MPa and 22%) of the Mg-11Li-6Zn alloy, presenting improvements of 11.8% and 22.7% in strength and ductility, respectively. The improvements in the mechanical properties of the Mg-11Li-6Zn alloy achieved by adding less Y could be attributed to the formation of moderate W phases and a reduction in grain size. However, once the addition of Y became excessive, the mechanical properties of the Mg-11Li-6Zn-1.2Y alloy were reduced due to the formation of too many reticular W phases. In addition, the Mg-11Li-6Zn-2Y alloy containing the highest Y content had the lowest ultimate tensile strength, 163 MPa, and highest ductility, 38%, due to the combined effect of the most reticular W phases and the smallest grains. Furthermore, the fracture morphology of the Mg-11Li-6Zn alloy displayed apparent necking, which became insignificant after the addition of Y, indicating that this addition could improve its uniform plastic deformation ability.https://www.mdpi.com/2075-4701/15/3/321Mg-Li alloymicrostructuremechanical propertyfracturealloying
spellingShingle Honghui Lin
Xuetao Ke
Guangxin Xiong
Binqing Shi
Zhengrong Zhang
Chuanqiang Li
The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
Metals
Mg-Li alloy
microstructure
mechanical property
fracture
alloying
title The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
title_full The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
title_fullStr The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
title_full_unstemmed The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
title_short The Effect of Rare Earth Y on the Microstructure and Mechanical Properties of an As-Cast Body-Centered Cubic Mg-11Li-6Zn Alloy
title_sort effect of rare earth y on the microstructure and mechanical properties of an as cast body centered cubic mg 11li 6zn alloy
topic Mg-Li alloy
microstructure
mechanical property
fracture
alloying
url https://www.mdpi.com/2075-4701/15/3/321
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