Stabilization of Al 3Zr Allotropes in Dilute Aluminum Alloys Via the Addition of Ternary Elements

29 Pages Posted: 28 Sep 2021

See all articles by Florian Schmid

Florian Schmid

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys

Dominik Gehringer

Montanuniversität Leoben - Department of Materials Science

Thomas Kremmer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Luigi Cattini

Montanuniversität Leoben - Christian Doppler Laboratory for Advanced Aluminum Alloys

Peter J. Uggowitzer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

David Holec

Montanuniversität Leoben - Department of Materials Science

Stefan Pogatscher

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Abstract

The formation of Al 3 Zr particles within dilute aluminum alloys can contribute effectively to controlling microstructure evolution and enhancing material properties. However, the possible transformation of Al 3 Zr from its initial metastable crystal structure L1 2 into its stable, tetragonal structure D0 23 is associated with faster coherency loss and the coarsening of Al 3 Zr particles. In this regard, our study aims at identifying ternary elements that can disrupt this mechanism. For this purpose, nine ternary Al-Zr-X alloys (Er, Sc, Hf, Y, Nb, Mn, Cu, Zn and Si) plus a base alloy (Al-Zr) were produced. Isochronal aging was performed at 475 °C and 550 °C, and an investigation of the particle landscape was carried out by STEM and HR-TEM. In parallel, we conducted ab initio calculations to investigate fundamental properties of ternary AlZrX-particles such as substitution likeliness, heat of formation and transformation mechanisms. The elements investigated show various behaviors. Fewer than half of the elements (Er, Sc, Hf and Si) are found to be incorporated into Zr-rich particles to any large extent; Er and Sc exhibit the well-known core-shell structure. Y and Zn do not interfere at all with the precipitation process. Nb, Mn and Cu form particles on their own, with Zr particles often attached to them. Concerning crystal structures, all element additions except for Y and Si widen the stability regime of L1 2.

Keywords: aluminum alloys, ab initio calculations, intermetallics, trialuminides

Suggested Citation

Schmid, Florian and Gehringer, Dominik and Kremmer, Thomas and Cattini, Luigi and Uggowitzer, Peter J. and Holec, David and Pogatscher, Stefan, Stabilization of Al 3Zr Allotropes in Dilute Aluminum Alloys Via the Addition of Ternary Elements. Available at SSRN: https://ssrn.com/abstract=3932308 or http://dx.doi.org/10.2139/ssrn.3932308

Florian Schmid (Contact Author)

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

Leoben, 8700
Austria

Dominik Gehringer

Montanuniversität Leoben - Department of Materials Science ( email )

Leoben
Austria

Thomas Kremmer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy ( email )

Leoben
Austria

Luigi Cattini

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

Leoben, 8700
Austria

Peter J. Uggowitzer

Montanuniversität Leoben - Chair of Nonferrous Metallurgy

Leoben
Austria

David Holec

Montanuniversität Leoben - Department of Materials Science ( email )

Leoben
Austria

Stefan Pogatscher

Montanuniversität Leoben - Chair of Nonferrous Metallurgy ( email )

Leoben
Austria

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