Machines. Technologies. Materials.
Vol. 19 (2025), Issue 3, pg(s) 110-113

MATERIALS

Application of thermal-derivative analysis to study phase transformation in AlSi7Mg alloy with different iron content

  • 1 Silesian University of Technology, Poland
  • 2 Superior IndustriesProduction Poland Sp. z o.o., Poland

Abstract

Using an increasing share of aluminum scrap (production and post-production) requires paying special attention to its impurities. Gaseous inclusions (e.g., hydrides) can be removed from the liquid alloy by refining, but the situation is worse with metallic impurities. In Al-Si alloys, one of the worst is iron, which goes into solution due to its low solubility in the solid state, at a content of over 0.4wt.%, it crystallizes in morphologically unfavorable phases, which worsen the functional properties and increase the porosity of aluminum alloys, limiting their use. The crystallization of these phases causes thermal effects that various methods can record. The paper presents studies of phase transformation, especially iron phases, using thermal-derivative analysis occurring in the AlSi7Mg alloy with different iron content. The studies were performed on Crystaldigraph NT3-8K coupled with the MLab program. It was found that the most unfavorable phase is β- Al5FeSi, which crystallizes preeutectic (and mainly primary crystallize) dimensions of up to 1000 μm, causing the formation of shrinkage porosities.

Keywords

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