Microstructural evolution and strengthening mechanism of high-strength AlSi8.1 Mg1.4 alloy produced by selective laser melting

Yaoxiang Geng; Qing Wang; Yingmin Wang; Qianhao Zang; Shaobo Mi; Junhua Xu; Yakai Xiao; Yi Wu; Junhua Luan

Materials & Design (Jun 2022)

Microstructural evolution and strengthening mechanism of high-strength AlSi8.1 Mg1.4 alloy produced by selective laser melting

Yaoxiang Geng,
Qing Wang,
Yingmin Wang,
Qianhao Zang,
Shaobo Mi,
Junhua Xu,
Yakai Xiao,
Yi Wu,
Junhua Luan

Affiliations

Yaoxiang Geng: School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China; Corresponding authors.
Qing Wang: Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
Yingmin Wang: Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
Qianhao Zang: School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Shaobo Mi: Jihua Laboratory, Foshan 528200, China
Junhua Xu: School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, China; Corresponding authors.
Yakai Xiao: State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, PR China
Yi Wu: State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, PR China
Junhua Luan: Center for Advanced Structural Materials, Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong 999077, China

Journal volume & issue: Vol. 218
p. 110674

Abstract

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A high-strength AlSi8.1Mg1.4 aluminum alloy was specifically designed for selective laser melting (SLM) by doubling the Mg content of A357 alloy based on the rapid solidification characteristics of the SLM process. The alloy showed good processability with maximum density over casting alloy with the same composition. The microstructure of the as-built alloy was characterized by the formation of cell structure. The α-Al cells manifested GP zones/Mg-Si clusters. The yield strength (YS), ultimate tensile strength (UTS), and elongation to fracture of the as-built alloy were 341 ± 14 MPa, 518 ± 6 MPa, and 7.1 ± 0.4%, respectively. Due to the precipitation of β″ nanoparticles in α-Al cells, the strength of the SLM alloy was effectively improved after direct aging at 150 ℃ and 200 ℃, with a maximum YS of 446 ± 5 MPa and maximum UTS of 546 ± 1 MPa, which were much higher than those of Al-Si-based alloy produced by SLM. When the aging temperature exceeded 200 ℃, the strength of the alloys decreased rapidly, but the elongation increased significantly. Multiple strengthening mechanisms, including grain refinement, GP zones/Mg-Si clusters, and β″ nanoparticle precipitation contributed to the high strength of SLM AlSi8.1Mg1.4 alloy.

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

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