Unraveling the Potential of Cu Addition and Cluster Hardening in Al-Mg-Si Alloys

37 Pages Posted: 29 May 2024

See all articles by Philip Aster

Philip Aster

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Phillip Dumitraschkewitz

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Peter J. Uggowitzer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Matheus Araujo Tunes

Montanuniversität Leoben; Government of the United States of America - Materials Science and Technology Division

Florian Schmid

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys

Lukas Stemper

AMAG rolling GmbH

Stefan Pogatscher

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys

Abstract

With the aim of further exploiting the trade-off between formability and strength in Al alloys, this study addresses the influence of Cu in Al-Mg-Si alloys that achieve simultaneously high strength and high ductility via cluster hardening. The study carefully examines the mechanical properties and strain hardening behavior of various Mg/Si ratios with and without Cu and compares the effects of pre-aging and atypical long-term low-temperature aging treatments at 100 °C to conventional heat treatments. Interestingly, in all cases adding Cu improved ductility. In the extremal case cluster hardening plus the addition of Cu quadruples elongation, while keeping yield strength similar to the classical T6 state. The results of the study are discussed with a focus on the dense distribution of clusters and partial hardening phases based on atom probe tomography data. Most importantly, the cluster-hardened alloys exhibit pronounced strain-hardening properties, which we evaluate using a Kocks-Mecking approach in combination with a microstructural analysis in the pre-aging and long-term aging condition. The key finding of the study involves the role of Cu in refining clusters/precipitates, where it causes a substantial increase in number density and volume fraction. This refinement, in combination with strain-induced clustering, contributes significantly to improving the alloys’ overall mechanical performance and underlines the central role of Cu in tailoring microstructural features, especially in alloys primarily strengthened by clusters.

Keywords: Aluminum alloys, Cluster hardening, Mechanical testing, Microstructure evolution, Dynamic recovery, APT

Suggested Citation

Aster, Philip and Dumitraschkewitz, Phillip and Uggowitzer, Peter J. and Tunes, Matheus Araujo and Schmid, Florian and Stemper, Lukas and Pogatscher, Stefan, Unraveling the Potential of Cu Addition and Cluster Hardening in Al-Mg-Si Alloys. Available at SSRN: https://ssrn.com/abstract=4843494 or http://dx.doi.org/10.2139/ssrn.4843494

Philip Aster (Contact Author)

Montanuniversität Leoben - Chair of Nonferrous Metallurgy ( email )

Phillip Dumitraschkewitz

Montanuniversität Leoben - Chair of Nonferrous Metallurgy ( email )

Peter J. Uggowitzer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Leoben
Austria

Matheus Araujo Tunes

Montanuniversität Leoben ( email )

Government of the United States of America - Materials Science and Technology Division ( email )

Los Alamos, NM 87545
United States

Florian Schmid

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys ( email )

Leoben, 8700
Austria

Lukas Stemper

AMAG rolling GmbH ( email )

Stefan Pogatscher

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys ( email )

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