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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (18권5호 439-449)

Formation of Oxide Inclusions in the Molten Aluminium Alloys

알루미늄합금 용탕중의 산화개재물 형성

Jeong-Ho Lim, Ki-Bae Kim*, Woo-Yung Yoon**, Eui-Pak Yoon

Hanyang University, *Korea Institute of Science and Technology, **Korea University

Abstract

Formation of oxide inclusions in the molten aluminium alloys during solidification is investigated. The oxidation tendency of both Al-4.5wt%Cu and Al-7wt%Si alloys is increased with melt temperature, particularly over 700℃. However, an Al-5wt%Mg alloy exhibits a decreasing mode over 800℃. The oxidation behavior with holding time shows the S curve shape for all of the alloys. It is shown that the mechanism of oxidation of Al-5wt%Mg alloy has a two step process different from that of Al-4.5wt%Cu and Al-7wt%Si alloys. The species and morphology of oxide inclusions in each alloy is also shown. The microstructure was more coarsened during solidification when the melt contains a large amount of oxide inclusion than when it doesn't. This result can be explained in terms of both the hindrance of heat extraction by oxide film formed on the aluminium melt and the difference of heat capacity between the aluminium melt and oxide inclusion during solidification.

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