Analysis of properties for in situ Al₂O₃p/A356 composites synthesised from the Al-SiO₂ system

Abstract

In situ Al2O3p/A356 composites with different particle volume fractions were successfully synthesised from the Al-SiO2 system by a direct-melt reaction. γ-Al2O3 was first produced during the reaction between Al and SiO2, and the phase transformation from γ-Al2O3 to α-Al2O3 then occurred at higher temperatures (1050°C), resulting in a volume contraction. The α-Al2O3p/A356 composite exhibited a reduction in dendrite cell size that was 1.5–2 greater than for the matrix alloy cast using the same conditions. A 10% particle volume fraction yielded optimum mechanical properties, with values for the yield stress, tensile strength, elongation and microhardness of 132 MPa, 268 MPa, 5.1% and 107.2 HV, respectively. These corresponded to increases 50, 31, 19 and 47%, respectively, when compared to the matrix. This paper is part of a thematic issue on Light Alloys.

Fabrication of Al-Ni-Al2O3 metal matrix composite coating on AA1100 wrought aluminium alloy by Gas Tungsten Arc (GTA) coating technique

“…[12][13][14]. Meng et al [15] used a direct-melt process to successfully produce Al 2 O 3 /A356 composites from the Al-SiO 2 system. The findings revealed that Al 2 O 3 particles crystallize at various temperatures, eventually creating Al 2 O 3 particles at about 1050 °C.…”

Light alloys

“…The original research articles that follow are then loosely grouped according to subject, commencing with studies on underpinning metallurgy [2][3][4][5], cast alloys [6][7][8], the properties and performance of extruded products [9][10][11][12], before moving to parallel tubular angular pressing [13] and selective laser melting [14]. The remaining articles deal with materials that may be considered to be composites based on an aluminium alloy, and these include an important contribution on foams [15], as well as contributions on synthesis [16] and the response of a composite to liquid-phase pulse impact treatment [17].…”