Microstructure and mechanical properties of thixoformed A319 aluminium alloy

Salleh, Mohd Shukor and Omar, Mohd Zaidi and Syarif, Junaidi and Alhawari, Khalid Salim and Mohammed, Mohamad Naser (2014) Microstructure and mechanical properties of thixoformed A319 aluminium alloy. Materials and Design, 64. pp. 142-152. ISSN 0261-3069

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Abstract

Thixoforming is a viable technology for forming alloys in a semisolid state into near net-shaped products. In the present study, the effect of a thixoforming process on the microstructure and mechanical properties of A319 aluminium alloy was investigated. The ingots obtained from the cooling slope were thixoformed in a press after they remained at 571 °C for 5 min, yielding a microstructure predominantly composed of α-Al globules and inter-globular Si particles. Some of the thixoformed samples were treated with an ageing process (T6) and then, hardness and tensile samples were prepared from the as-cast, as-thixoformed and thixoformed T6. All the thixoformed samples were characterised using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) as well as hardness measurements and tensile tests. The results indicate that the mechanical properties of the thixoformed A319 alloy increased after the T6 heat treatment (hardness of 124.2 ± 3.2 HV, tensile strength of 298 ± 3.0 MPa, yield strength of 201 ± 2.6 MPa and elongation to fracture of 4.5 ± 0.3%). The fracture samples from the tensile test were analysed, revealing that the iron-rich intermetallic observed in the samples reduced the tensile strength and ductility of the thixoformed A319 alloys.

Item Type:	Article
Uncontrolled Keywords:	Aluminium alloy, cooling slope casting, thixoforming, T6 heat treatment
Subjects:	T Technology > TJ Mechanical engineering and machinery
Divisions:	Faculty of Manufacturing Engineering > Department of Manufacturing Process
Depositing User:	Dr MOHD SHUKOR SALLEH
Date Deposited:	03 Mar 2015 08:03
Last Modified:	28 May 2015 04:37
URI:	http://eprints.utem.edu.my/id/eprint/14262
Statistic Details:	View Download Statistic

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