A Hybrid Joining Strategy for Al–Cu Bimetallic Sheets Produced by Friction Stir Welding

The production of Al–Cu bimetallic sheets is of increasing interest for applications requiring a combination of lightweight performance and high thermal or electrical conductivity. Conventional fusion welding techniques are unsuitable due to excessive intermetallic compound (IMC) formation and poor bonding quality. Solid-state processes such as Friction Stir Welding (FSW) provide an attractive alternative; however, most studies aim to minimize heat input in order to suppress IMCs. In this work, a different approach is proposed. A hybrid joining strategy is employed, intentionally using controlled heat input and tool penetration to generate an extended stirring zone and a pronounced hook geometry. This results in mechanical interlocking combined with metallurgical bonding at the Al–Cu interface. Large-area bimetallic sheets were fabricated by FSW lap welding using four parallel passes to enlarge the bonded region. Microstructural characterization revealed the formation of continuous hook structures along the interface, promoting effective mechanical interlocking between the aluminum and copper layers. The integrity of the bimetallic sheets was further evaluated by cold rolling, which demonstrated excellent resistance to delamination despite local cracking of brittle IMCs. The results confirm that exploiting hook formation, rather than suppressing it, can provide a robust and scalable strategy for manufacturing Al–Cu bimetallic sheets by FSW.

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Periodical:

Materials Science Forum (Volume 1185)

Pages:

69-76

DOI:

https://doi.org/10.4028/p-x7LK1s

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Online since:

April 2026

Authors:

Ioannis Papantoniou*, Dimitrios E. Manolakos

Keywords:

Al–Cu, Bimetallic Sheets, Friction Stir Welding, Hybrid Joining Strategy

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Creative Commons CC BY 4.0

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* - Corresponding Author

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