Ефективність модифікування заевтектичного силуміну дрібнокристалічною лігатурою al–р: Processy litʹâ, 2021, Tom 146, №4, p.40-47

• Date: 2021
• Main Authors: Сінчук, А. В., Меркулов*, О.Є.
• Format: Article
• Language: Ukrainian
• Published: National Academy of Sciences of Ukraine, Physical-Technological Institute of Metals and Alloys of NAS of Ukraine 2021
• Subjects: заевтектичний силумін; модифікування; крупнокристалічна (дрібнокристалічна) лігатура; фосфід алюмінію; первинний кремній; рафінування
• Online Access: https://plit-periodical.org.ua/index.php/plit/article/view/81
• Journal Title: Casting Processes

Received 21.10.2021 UDK 621.746.6:669.715-41 Comparative results of modifying the hypereutectic A390 silumin by means of a binary Al–3P master alloy having different structural and dimensional state are presented. Fine-crystalline master alloy with phosphide inclusions evenly distributed within the aluminum matrix and sized of 5–10 μm and less was obtained shaped in thin plates after remelting under a protective atmosphere and rapid cooling a commercial coarse-grained tablet master alloy, which contained individual particles and their conglomerates larger than 200 μm alongside the dispersed inclusions. Remelting also contributed to the more numerous phosphide inclusions, probably, due to chemical reactions involving residual elemental phosphorus of the commercial master alloy. Primary Si crystals in A390 alloy after modification with the fine-crystalline master alloy are crushed 1.2–2.5 times and its mechanical properties are improved in comparison with the alloy modified with the large-crystalline one. It was determined, according to the cooling curves that primary crystallization of the silumin modified with the fine-grained master alloy takes place without the latent heat release and starts at the temperature 5 °C higher than the onset crystallization temperature for A390 alloy which the coarse-grained master alloy was added to. It is also shown the dispersion of the cast structure of A390 alloy, including eutectic one, modified with the fine-crystalline master alloy increases, and the elongation rises up to 2 % in sequence "unrefined alloy" – "alloy refined with hexachloroethane" – "alloy refined by Ar purging.