Simultaneous improvement in strength and ductility of friction stir welded Mg/Al joints by reducing micro-intermixing

Xuesong Fu; Ke Chen; Qingsong Zhang; Siqi Liu; Nannan Chen; Min Wang; Xueming Hua

Journal of Materials Research and Technology (Jul 2024)

Simultaneous improvement in strength and ductility of friction stir welded Mg/Al joints by reducing micro-intermixing

Xuesong Fu,
Ke Chen,
Qingsong Zhang,
Siqi Liu,
Nannan Chen,
Min Wang,
Xueming Hua

Affiliations

Xuesong Fu: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China
Ke Chen: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; Corresponding author. Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China.
Qingsong Zhang: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China
Siqi Liu: Shanghai Aerospace Equipment Manufacture, 200245, Shanghai, People's Republic of China
Nannan Chen: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China
Min Wang: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China
Xueming Hua: Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China; School of Materials Science and Engineering, Shanghai Jiao Tong University, 200240, Shanghai, People's Republic of China

Journal volume & issue: Vol. 31
pp. 1379 – 1391

Abstract

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Thread of pin has been proved beneficial to increasing shear action of tool and material intermixing, which however induces abundant formation of intermetallic compounds (IMCs) in Mg/Al dissimilar friction stir welding (FSW) leading to deteriorating the performance of joints. In this work, Mg alloy and Al alloy were well joined by threaded pin and unthreaded pin under the same welding parameters. For threaded pin joints, cracks occured in the banded structure (BS) region and bottom interface, then the main crack propagated along the Mg/Al interface, resulting in low strength and elongation. For unthreaded pin joints, necking and fracture occurred at the softened Al alloy to the retreating side (SAA-RS), and the fracture mode changed from brittle fracture (Mode I) to ductile fracture (Mode III). The tensile strength and strain of unthreaded pin joints are 201 MPa and 7.14 % respectively, significantly higher than those of threaded pin joints (i.e. 140 MPa and 1.15 %), and is the highest combination of strength and strain reported up until now. An unthreaded pin could reduce the local micro-intermixing between Mg and Al to suppress the formation of IMCs, which reduced the hardness in the BS region, preventing the formation and propagation of cracks.

Published in Journal of Materials Research and Technology

ISSN: 2238-7854 (Print); 2214-0697 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Mining engineering. Metallurgy
Website: https://www.journals.elsevier.com/journal-of-materials-research-and-technology/

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