Development of high strength suction cast hypereutectic Al–20Si alloy containing gamma alumina and strontium

ABSTRACT

In this research, the hypereutectic Al–20Si alloy, containing an optimised amount of 4 wt-% γ-Al₂O₃ and 0.1 wt-% strontium, was successfully synthesised through the suction casting process. The cooling rate (563 K s⁻¹) involved during solidification was estimated by measuring secondary dendritic arm spacing. As a result, a significant change in the morphology of silicon was observed and also led to the formation of a small fraction of refined α-Al throughout the microstructure. The work demonstrates that high tensile properties in hypereutectic Al–20Si alloys can be achieved without the use of conventional inoculants (such as phosphorus). The suction cast Al–20Si alloy exhibits remarkably enhanced tensile properties of average ultimate tensile strength of 355 MPa and average ductility of 7.1%.

KEYWORDS:

• Suction casting
• aluminium alloy
• modification
• primary Si
• eutectic Si
• tensile strength

Acknowledgements

The authors would like to show their gratitude to the Indian Institute of Science Bangalore, India for providing vacuum arc melting furnace for suction casting and tensile testing facilities which constitute an essential part of the analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Mihira Acharya http://orcid.org/0000-0002-2652-0018