Influence of Si Addition on Oxide Growth of Al-6 mass%Mg Alloy Melts

• Published in: Archives of metallurgy and materials Vol. 66; no. 3; pp. 695 - 698
• Main Authors: Yoon, Young-Ok, Ha, Seong-Ho, Shah, Abdul Wahid, Kim, Bong-Hwan, Lim, Hyun-Kyu, Kim, Shae K
• Format: Journal Article
• Language: English
• Published: Warsaw Polish Academy of Sciences 2021
• Subjects: al-mg system; Alloying additive; Alloys; Aluminum; Clusters; Magnesium base alloys; Mixed oxides; oxidation; phase diagram; si addition; Silicon
• ISSN: 1733-3490; 2300-1909
• DOI: 10.24425/amm.2021.136363

Influence of Si addition on oxide layer growth of Al-6 mass%Mg alloys in molten state was investigated in this study. After melt holding for 24 h, the melt surface of only Si-free alloy became significantly bumpy, while no considerably oxidized surface was observed even with 1 mass%Si addition. There was no visible change on the appearance of melt surfaces with increasing Si content. As a result of compositional analysis on the melt samples between before and after melt holding, the Si-added alloys nearly maintained their Mg contents even after the melt holding for 24 h. On the other hand, the Mg content in the Si-free alloy showed a great reduction. The bumpy surface on Si-free alloy melt showed a large amount of pores and oxide clusters in its cross-section, while the Si-added alloy had no significantly grown oxide clusters on the surfaces. As a result of compositional analysis on the surfaces, the oxide clusters in Si-free alloy contained a great amount of Mg and oxygen. The oxide layer on the Si-added alloy was divided into Mg-rich and Mg-poor areas and contained certain amounts of Si. Such a mixed oxide layer containing Si would act as a protective layer during the melt holding for a long duration.