Králík, R.; Bajtošová, L.; Kihoulou, B.; Preisler, D.; Cieslar, M. High-Temperature Phase Transformations in Al-Li-Cu-Mg-Zr-Sc Alloy Studied via In Situ Electron Microscopy. Crystals2024, 14, 136.
Králík, R.; Bajtošová, L.; Kihoulou, B.; Preisler, D.; Cieslar, M. High-Temperature Phase Transformations in Al-Li-Cu-Mg-Zr-Sc Alloy Studied via In Situ Electron Microscopy. Crystals 2024, 14, 136.
Králík, R.; Bajtošová, L.; Kihoulou, B.; Preisler, D.; Cieslar, M. High-Temperature Phase Transformations in Al-Li-Cu-Mg-Zr-Sc Alloy Studied via In Situ Electron Microscopy. Crystals2024, 14, 136.
Králík, R.; Bajtošová, L.; Kihoulou, B.; Preisler, D.; Cieslar, M. High-Temperature Phase Transformations in Al-Li-Cu-Mg-Zr-Sc Alloy Studied via In Situ Electron Microscopy. Crystals 2024, 14, 136.
Abstract
A homogenization of billets from Al-Cu-Li-Mg-Sc-Zr alloys should be accomplished at high annealing temperatures exceeding 500 °C. This type of aluminum alloy is susceptible to the depletion of surface layers from Li. Therefore, choosing a suitable homogenization temperature and duration is a crucial step in assuring a homogeneous distribution of alloying elements and optimal exploitation of the potential of the alloy. In-situ heating in an electron microscope was performed on a twin-roll cast Al-Cu-Li-Mg-Sc-Zr alloy to understand the peculiarities of the homogenization process. Four types of primary phase particles rich in Cu, Li, Mg, and Fe were identified in the as-cast material. They appear as coarse particles at the boundaries of eutectic cells. Their partial dissolution occurs at temperatures above 450 °C. They are almost fully dissolved at 550 °C, except for complex phases containing Fe and Cu. Small dimensions of eutectic cells in the range of 10 µm assure a homogeneous distribution of main alloying elements within the matrix after 20 min of annealing. Direct comparison with the same material prepared by mold-casting indicates that such short annealing times result in the dissolution of main primary phase particles but do not assure a homogeneous distribution of alloying elements in the whole volume of the specimen.
Engineering, Metallurgy and Metallurgical Engineering
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