The effects of cooling slope on the semi-solid microstructures of Al4.8Si2.8Cu0.5Mg aluminium alloy / Mohd Anif Mohd Arif ... [et al.]

Mohd Arif, Mohd Anif and Omar, Mohd Zaidi and Sajuri, Zainuddin and Mohamed, Intan Fadhlina and Samat, Saziana (2018) The effects of cooling slope on the semi-solid microstructures of Al4.8Si2.8Cu0.5Mg aluminium alloy / Mohd Anif Mohd Arif ... [et al.]. Journal of Mechanical Engineering (JMechE), SI 7 (1). pp. 231-239. ISSN 18235514


Thixoforming process is a metal forming process in the semi-solid condition to produce near net shaped products. The key requirement of the thixoforming process is the production of feedstock materials that consists of solid spheroids in the liquid matrix, rather than dendrites. The solid spheroidal structure could not be generated if the gravity cast alloy that consists of the dendritic structure
is directly subjected to partial remelting. Cooling slope casting process is one of the simplest and cheapest methods that can be utilised to produce the nondendritic structure. In the present study, the effects of cooling slope casting
process on the microstructure of Al4.8Si2.8Cu0.5Mg aluminium alloy were investigated. The alloy was melted at a superheated temperature of 700 °C before cooled down to the selected pouring temperature (650 °C) and subsequently poured onto a stainless steel plate with the cooling length of 400 mm. The plate was tilted at 60° from horizontal and was cooled with water circulation underneath to promote the nucleation of fine α–Al particles.
Finally, the poured molten metal was collected in a 150 °C preheated cylindrical stainless steel mould. The alloy billet that consists non-dendritic αgrains with a shape factor of 0.74±0.13 and an average primary particle size
of 31.94±6.76 µm was successfully produced from gravity cast alloy with a dendritic microstructure by cooling slope casting process. After partial remelting at 575 °C, the non-dendritic structure has changed into fine solid spheroidal α-Al grains with a shape factor of 0.84±0.06 and an average
primary particle size, approximately 35.92±9.13 µm. These solid spheroidal
structures surrounded by a liquid matrix may be offer thixotropic behaviour
and suitable for thixoforming applications.


Item Type: Article
Email / ID Num.
Mohd Arif, Mohd Anif
Omar, Mohd Zaidi
Sajuri, Zainuddin
Mohamed, Intan Fadhlina
Samat, Saziana
Subjects: T Technology > TA Engineering. Civil engineering > Engineering machinery, tools, and implements
T Technology > TJ Mechanical engineering and machinery
Divisions: Universiti Teknologi MARA, Shah Alam > Faculty of Mechanical Engineering
Journal or Publication Title: Journal of Mechanical Engineering (JMechE)
UiTM Journal Collections: UiTM Journal > Journal of Mechanical Engineering (JMechE)
ISSN: 18235514
Volume: SI 7
Number: 1
Page Range: pp. 231-239
Keywords: Cooling slope; Semi-solid; Thixoforming; Microstructure; Aluminium alloy
Date: 2018
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