Study of the effect of hafnium and erbium content on the formation of microstructure in aluminium alloy 1590 cast into a copper chill mold

OBRABOTKAMETALLOV Vol. 26 No. 1 2024 110 MATERIAL SCIENCE References 1. Alattar A.L.A., Bazhin V.Yu. Kompozitsionnye materialy Al-Cu-B4C dlya polucheniya vysokoprochnykh zagotovok [Al-Cu-B4C composite materials for production of high-strength workpieces]. Metallurg = Metallurgist, 2020, no. 6, pp. 65–70. (In Russian). Study of the effect of hafnium and erbium content on the formation of microstructure in aluminium alloy 1590 cast into a copper chill mold Aleksandr Ragazin 1, a, *, Vladimir Aryshenskii 1, b, Sergey Konovalov 1, 2, c, Evgenii Aryshenskii 1, 2, c, Inzil Bakhtegareev 1, c 1 Samara National Research University named after S.P. Korolev, 34 Moskovskoe Shosse, Samara, 443086, Russian Federation 2 Siberian State Industrial University, 42 Kirova str., Novokuznetsk, 654007, Russian Federation a https://orcid.org/0000-0002-6762-7436, aleksander.ragazin@samara-metallurg.ru; b https://orcid.org/0000-0001-6869-4764, arysh54@mail.ru; c https://orcid.org/0000-0003-4809-8660, konovalov@sibsiu.ru; d https://orcid.org/0000-0003-3875-7749, arishenskiy_ev@sibsiu.ru; e https://orcid.org/0009-0004-3081-9049, bakhtegareev.id@ssau.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2024 vol. 26 no. 1 pp. 99–112 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2024-26.1-99-112 ART I CLE I NFO Article history: Received: 12 September 2023 Revised: 23 September 2023 Accepted: 16 November 2023 Available online: 15 March 2024 Keywords: Aluminum Lean doping with scandium Hafnium, Erbium Microstructure Intermetallic compounds Funding The study was supported by a grant of the Russian Science Foundation, project No. 22-19-00810, https://rscf.ru/ project/22-19-00810/ ABSTRACT Introduction. High-magnesium aluminum alloys are widely used in the automotive, building and aerospace industries due to its low specifi c gravity and high strength. The characteristics of such alloys can be improved by small additions of scandium and zirconium. However, scandium is very expensive, so in new generation alloys its amount is tended to be reduced. In the recently developed 1590 aluminum alloy, this was achieved by addition of erbium and hafnium. The objective of the paper is to study the eff ect of erbium and hafnium concentrations on the modifi cation of the cast structure in 1590 aluminum alloy at high solidifi cation rates. Research Methods. The paper investigates the microstructure, chemical composition and size of intermetallic compounds in specimens from ten alloy 1590 modifi cations with diff erent hafnium and erbium contents cast into a copper chill mold with a solidifi cation rate of 10 °C/sec. The grain structure was studied using an optical microscope. The chemical composition and size of the intermetallic phases were studied using a Tescan Vega 3 scanning electron microscope. Results and discussion. It is established that as the amount of hafnium and erbium increases, the cast structure is modifi ed. In general, grain refi nement with the addition of hafnium and erbium can be explained by a higher degree of supercooling between the solid and liquid phases. At a hafnium content of 0.16 %, the dendritic structure begins to transform into an equiaxed grain structure. This transformation can be explained by the appearance of primary intermetallic compounds of the Al3Sc type in the liquid phase. Such intermetallic compounds are identifi ed at a concentration of erbium and hafnium equal to 0.16 %. Moreover, in all alloys eutectic intermetallic compounds are identifi ed that contained manganese and iron and had no eff ect on the cast structure. Comparison with previously obtained results on the grain size of specimens cast into a steel mold shows that with higher solidifi cation rate, the structure modifi cation in 1590 alloy is getting less effi cient. This is explained by an increase in the concentration of transition elements in the solid solution, primarily scandium, necessary for the formation of primary intermetallic particles. For citation: Ragazin A.A., Aryshenskii V.Y., Konovalov S.V., Aryshenskii E.V., Bakhtegareev I.D. Study of the eff ect of hafnium and erbium content on the formation of microstructure in aluminium alloy 1590 cast into a copper chill mold. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 1, pp. 99–112. DOI: 10.17212/1994-6309-2024-26.199-112. (In Russian). ______ * Corresponding author Ragazin Alexander A., Post-graduate Student Samara National Research University named after S.P. Korolev, 34 Moskovskoe Shosse, 443086, Samara, Russian Federation Tel.: +7 917 125-64-91, e-mail: aleksander.ragazin@samara-metallurg.ru

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