Identification of Fe-bearing phases in the as-cast microstructure of AA6026 alloy and their evolution during homogenization treatment

  • Tamara Radetic University of Belgrade, Faculty of Technology and Metallurgy
  • Miljana Popović University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia
  • Mirjana Novaković University of Belgrade, Department of Atomic Physics, Vinča Institute of Nuclear Sciences – National Institute of the Republic of Serbia, Belgrade, Serbia
  • Vladimir Rajić University of Belgrade, Department of Atomic Physics, Vinča Institute of Nuclear Sciences – National Institute of the Republic of Serbia, Belgrade, Serbia
  • Endre Romhanji University of Belgrade, Faculty of Technology and Metallurgy, Belgrade, Serbia
Keywords: 6xxx alloys, Fe-bearing microconstituents, δ-Al4(Fe,Mn)Si2 phase, Homogenization, Phase transformation

Abstract


The Fe-bearing intermetallic phases present in the as-cast AA6026 alloy and their evolution during homogenization treatments at 480-550°C were investigated using optical microscopy, SEM, and TEM techniques in combination with EDS analysis. In addition to the α-Al(Fe,Mn)Si phase with dendritic morphology, two types of plate-like Fe-bearing microconstituents were revealed in the microstructure of the as-cast alloy. The EDS microanalysis and electron diffraction showed that one set of platelets represented only thin sections of α-Al(Fe,Mn)Si microconstituent. The other set of plate-like microconstituents was identified as a tetragonal, silicon-rich δ-Al4(Fe,Mn)Si2 phase. The formation of the δ-Al4(Fe,Mn)Si2 phase was attributed to the chemical composition of the alloy. During homogenization, the metastable δ-Al4(Fe,Mn)Si2 transformed into the α-Al(Fe,Mn)Si phase and fragmented. The dendritic α-Al(Fe,Mn)Si microconstituents were also fragmented. However, while the α-Al(Fe,Mn)Si microconstituents preserved a b.c.c. crystal lattice throughout the process, the product of the transformation of the δ-Al4(Fe,Mn)Si2 phase exhibited primitive cubic lattice.

 

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Published
2023/12/01
How to Cite
Radetic, T., Popović, M., Novaković, M., Rajić, V., & Romhanji, E. (2023). Identification of Fe-bearing phases in the as-cast microstructure of AA6026 alloy and their evolution during homogenization treatment. Journal of Mining and Metallurgy, Section B: Metallurgy, 59(2), 327-338. Retrieved from https://aseestant.ceon.rs/index.php/jmm/article/view/45445
Issue
Vol. 59 No. 2 (2023)
Section
Original Scientific Paper

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