The role of iron in the formation of porosity in Al-Si-Cu-based casting alloys. Part 2: A phase-diagram approach

Journal Article · Tue Jun 01 00:00:00 EDT 1999 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-999-0102-0· OSTI ID:677976

Taylor, J A; Schaffer, G B; StJohn, D H ^[1]

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1. Univ. of Queensland, Brisbane (Australia)

The mechanism by which iron causes casting defects in the AA309 (Al-5 pct Si-1.2 pct Cu-0.5 pct Mg) may be related to the solidification sequence of the alloy. Superimposing calculated segregation lines on the liquidus projection of the ternary Al-Si-Fe phase diagram suggests that porosity is minimized at a critical iron content when solidification proceeds directly from the primary field to the ternary Al-Si-{beta}Al{sub 5}FeSi eutectic point. Solidification via the binary Al-{beta}Al{sub 5}FeSi eutectic is detrimental to casting integrity. This hypothesis was tested by comparing the critical iron content observed in the standard AA309 alloy to that of a high-silicon (10 pct Si) variant of this alloy.

• Sponsoring Organization: USDOE
• OSTI ID: 677976
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 30, Issue 6; Other Information: PBD: Jun 1999
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PORE STRUCTURE
ALUMINIUM ALLOYS
SILICON ALLOYS
COPPER ALLOYS
MAGNESIUM ALLOYS
IRON ADDITIONS
LIQUID METALS
SOLIDIFICATION
PHASE STUDIES