Tackling Fe-rich Intermetallics in Al-Si Alloy: A Critical Review

• Published in: Transactions of the Indian Institute of Metals Vol. 77; no. 10; pp. 3031 - 3036
• Main Authors: Kishor, Modalavalasa, Chopra, Kunal, Ayyagari, Kameswari Prasada Rao
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.10.2024; Springer Nature B.V
• Subjects: Alloying; Alloys; Aluminum; Aluminum base alloys; Aspect ratio; Casting; Chemistry and Materials Science; Corrosion and Coatings; Fragility; Intermetallic compounds; Materials Science; Mechanical properties; Metal scrap; Metallic Materials; Morphology; Original Article; Recycling; Scrap iron; Silicon; Tensile strength; Tribology; Nucleation; Al-Si alloys; Fe-rich intermetallics; Growth; Solidification
• ISSN: 0972-2815; 0975-1645
• DOI: 10.1007/s12666-023-03205-8

Iron-rich intermetallics in Al-Si alloys pose a major challenge in aluminum recycling. Virgin Al-Si alloys typically contain a minimal iron concentration which enhances properties like tensile strength and conductivity. Although aluminum is a recycling friendly metal, Fe impurity increases due to scrap contaminations, coatings and rust, which eventually leads to the evolution and growth of detrimental Fe-rich intermetallics. These Fe-rich particles exhibit platelet or needle-like morphologies, and their aspect ratios grow with higher Si and Fe concentrations. Among the identified β phases, β -Al 5 FeSi is predominantly known for its fragility and negative impact on the mechanical properties of the alloy. Two potential solutions to this problem are, removing Fe from Al-Si alloys or suppressing the formation of β -Al 5 FeSi. While the method of alloying additions is much more viable for industry scale. Current study is a critical review of morphological modification of Fe-rich intermetallics through alloying additions to Al-Si alloys. The independent mechanism(s) of suppression of β -Al 5 FeSi phase by Mn, Mo, V and Cr additions is discussed along with the challenges and future scope of this work are discussed in detail.