Investigation of the Solidification Rate in Twin-Roll Cast and Rolled Zr Microalloyed Al-Mg-Si Aluminum Alloys: a Molecular Dynamics Approach

Wenlin Gao, Junzhou Chen, Ruijue Wang, Jicheng Wang, Feng Sun, and Chengning Li

DOI: https://doi.org/10.64486/m.66.1.2
Online publication date: May 15, 2026

Abstract: The present study investigated the impact of Zr microalloying on the solidification mechanism and rate of cast-rolled Al-Mg-Si aluminum alloy, using differential scanning calorimetry, light microscopy, and PandatTM thermodynamic calculations. The molecular dynamics models of three different systems were established: Al-pure, Al-0.1Zr and Al-0.3Zr. The results revealed that an optimal amount of Zr effectively reduced the nucleation barrier at the atomic level during alloy solidifi-cation. This reduction facilitated the formation of critical nuclei, promoted the transformation of hexagonal close-packed clusters into face-centered cubic clusters, altered the mechanism of grain nucleation and growth, and enhanced the solidus temperature of the cast-rolled alloy. Consequently, the temperature range of the solid-liquid two-phase region was narrowed, leading to a substantial in-crease in the alloy’s solidification rate. These atomic-scale findings enhance un-derstanding of Zr’s role in solidification control, offering a basis for designing high-performance aluminum alloys and guiding industrial twin-roll casting processes.

Keywords: molecular dynamics; twin-roll casting and rolling; solidification rate; aluminum alloy

This article is published online first and will appear in Metalurgija, Vol. 66, Issue 1 (2027).