Title: Influence of heat treatment on the microstructures and mechanical properties of squeeze cast AlSi₉Cu₃ alloys

Authors: Henda Barhoumi; Slim Souissi; Mohamed Ben Amar; Foued Elhalouani

Addresses: Faculty of Sciences of Sfax (FSS), University of Sfax, B.P. 802-3038, Tunisia ' National Engineering School of Sfax (ENIS), University of Sfax, B.P. 599-3038, Tunisia ' National Engineering School of Sfax (ENIS), University of Sfax, B.P. 599-3038, Tunisia ' National Engineering School of Sfax (ENIS), University of Sfax, B.P. 599-3038, Tunisia

Abstract: The AlSi₉Cu₃ alloy was prepared by gravity die casting and squeeze casting. This alloy has a good castability, excellent machinability, medium strength and low specific weight. Various test techniques, including optical microscopy, scanning electron microscope, X-ray diffraction, tensile test and hardness were used to examine the effect of pressure levels and T6 heat treatment on the microstructure and mechanical properties of Al₉Si₃Cu alloy produced by gravity and squeeze casting process. The experimental results showed that this alloy contained α-matrix, eutectic silicon and other Fe- and Cu-rich phases with different morphology. Furthermore, the applied pressure refines the microstructure, improves the tensile properties and increases the hardness Vickers. It was found that a T6 heat treatment was applied, spheroidised eutectic Si particles and fragmented β-phase particles were formed and the mechanical properties were improved.

Keywords: mechanical properties; microstructure; T6 heat treatment; pressure; SDAS; secondary dendrite arm spacing; AlSi9Cu3; aluminium alloys; squeeze casting; gravity die casting; tensile testing; hardness.

DOI: 10.1504/IJMMP.2015.074999

International Journal of Microstructure and Materials Properties, 2015 Vol.10 No.5/6, pp.472 - 487

Received: 31 Oct 2015
Accepted: 28 Dec 2015
Published online: 28 Feb 2016 *

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