Akademik Veri Yönetim Sistemi
JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, cilt.40, sa.2, 2025 (SCI-Expanded, Scopus, TRDizin)
Purpose: The aim of this study is to examine the effect of microsegregation of a certain amount of zirconium transition element added to a commercial aluminum alloy on the casting microstructure of the alloy and the recrystallization behavior of the alloy under subsequent process conditions. Theory and Methods: In the experimental study, the alloys were cast in industrial sizes by the semi- continuous casting method, their microstructures were examined microscopically and the phases formed in the casting were determined. Electron probe microanalysis was performed to examine the microsegregation of Zr, Mg, Fe, Mn and Cr in the as-cast alloys. Then, the alloys were homogenized in accordance with industrial conditions. Samples taken from homogenized alloys were annealed after cold deformation. The effect of Zr microsegregation on recrystallization behavior was examined by EPMA of these samples. Results: In the AlMgSi1Mn alloy, zirconium segregated to the dendrite centers during casting and formed plate-like (Al,Si)3Zr primary intermetallic compounds due to the high Si content of the alloy. These compounds played a role in the refinement of grain size by acting as nuclei due to the peritectic reaction formed by Al and Zr. In subsequent processes, zirconium formed stable and fine secondary Al3Zr precipitates. Recrystallization was prevented by these fine precipitates in regions where the solubility limit of Zr was exceeded. Conclusion: The fibrous structure formed as a result of deformation during or after the plastic shaping and heat treatments of the alloy may disappear and a recrystallized coarse-grained structure may form instead. This situation causes the alloy's properties such as strength and toughness to decrease. Therefore, experimental study has shown that Zr, a transition element, affects the microstructure and recrystallization behavior of the alloy with different mechanisms, thanks to the precipitates with different compounds and properties it forms. Forming as many Zr-based compounds in the structure as possible and distributing them homogeneously throughout the matrix will increase these effects more positively. For this reason, Zr microsegregation during these processes is an important issue that needs to be known in terms of its effect on the microstructure components and alloy properties that will be formed.