The structure and properties evolution of Al-Zn-Mg-Cu-Sc-Zr alloy after heat treatments
DOI:
https://doi.org/10.15407/mom2026.01.013Keywords:
high-strength aluminum alloy, scandium, zirconium, MHD, mechanical propertiesAbstract
This study is focused on the development and comprehensive analysis of the structural state and mechanical properties of a high-strength wrought aluminum alloy of the Al–Zn–Mg–Cu system, additionally alloyed with scandium (Sc) and zirconium (Zr). Alloys of this system are critically important materials for the aviation and defense industries due to their exceptional specific strength. The research addresses common challenges inherent to high-alloyed systems, such as susceptibility to hot cracking and dendritic segregation, by optimizing alloying element content and implementing innovative casting techniques.
The scientific novelty of this work lies in the investigation of the synergistic effect of Sc and Zr on the alloy's microstructure specifically in the as-cast state, an area less explored compared to wrought semi-finished products. It was established that the formation of Al3(Sc, Zr) intermetallic compounds ensures significant grain refinement, enhances anti-recrystallization stability, and contributes to additional strengthening through the precipitation of secondary coherent nanoparticles that remain stable during subsequent heat treatment.
The practical part of the research involved the production of a large-scale industrial ingot (150 mm in diameter) using a vacuum magnetohydrodynamic (MHD) installation and continuous casting into a short crystallizer with a thermal filling. This approach facilitated a uniform globular structure free of gas porosity, achieving a record-low hydrogen content (0.04–0.05 cm³/100 g). The evolution of the microstructure and phase transformations was studied using SEM, EDS, and DSC methods.
Mechanical testing results demonstrated that the applied casting technology ensures high isotropy of properties in both longitudinal and transverse directions. The alloy was found to exhibit high technological plasticity (elongation up to 53%) at temperatures of 300–400 °C, allowing for the optimization of further thermomechanical processing parameters, such as forging and rolling. The initial interphase melting temperature was determined to be 471–477 °C, serving as a fundamental parameter for establishing precise homogenization and solution treatment regimes for the experimental alloy.
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Copyright (c) 2026 O. A. Davydenko, A. V. Narivsky, S. L. Polyvoda, V. I. Bondarchuk, О. А. Molebnyi, O. F. Tarasov, V. O. Tverdokhvalov, D. Sindalovsky, D. S. Kytranov, A. Yu. Semenko, M. M. Voron
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