Joining characteristics of oxidized SiC particles reinforced Al–Mg matrix composite prepared by reaction infiltration processing

Abstract

The joining characteristics of oxidized SiC particles with Al–Mg alloy during reaction infiltration processing for fabrication of the composite were studied. From the measurement of weight changes due to the transformation from SiC into SiO2, it became clear that the thickness of SiO2 layer which was formed at the surface of SiC particles increased parabolically with holding time at the given exposing temperatures. The degree of oxidation of the preform made by SiC particles can be controlled by the application of the present oxidation data. The microstructure observed by field emission scanning electron microscopy showed network skeleton via necklike oxidized-joining among the SiC particles and the compressive strength of the perform increased with oxidation temperature. Furthermore, the microstructure of the composite which was fabricated by Al–2 wt% Mg alloy via reaction infiltration processing was examined and the formation of spinel was observed to join the matrix with the particles like a bridge, which is suitable to make the complicate and strong preforms for the near net-shape composites application in electronic packaging.

Effect of SiCp multimodal distribution on pitting behavior of Al/SiCp composites prepared by reactive infiltration

“…5 and 6 show typical diffractograms corresponding to composites with monomodal, bimodal, trimodal, and cuatrimodal distributions, before and after the electrochemical tests, respectively. According to thermodynamics and previous works [6,7,19,20], silica reacts with the aluminum alloy (in the presence of Mg), giving place to the formation of spinel and magnesium oxide. In this particular investigation, since silica is forming coatings on the SiC particles, the abovementioned interactions avoid the attack of the SiC particles by the molten alloy and in consequence, successfully avoided …”

“…Subsequent exposure of the composites to liquid water or moisture leads to a gradual degeneration of the composites. Several approaches have been proposed and practiced to avoid formation of this deleterious phase, namely: a) additions of Si into the Al matrix [5], b) artificial oxidation to produce a SiO 2 layer on SiC [6], and c) incorporation of silica particles into the porous SiC preforms [7,8]. All these approaches can be conducive to the in situ formation or precipitation of new phases.…”

Surface chemistry modification for elimination of hydrophilic Al4C3 in B4C/Al composites

“…Such techniques include modification of the chemical composition of the matrix [9,17,27], control of the processing parameters [23], surface modification of the reinforcements [16] and additions of SiO 2 to the reinforcements [9,10,28]. Most of the works reported in the related literature have focused on preventing Al 4 C 3 formation during processing.…”

Microstructure and impact behavior of Al/SiCp composites fabricated by pressureless infiltration with different types of SiCp

“…For example, tailoring the aluminum alloy with surfactant elements such as Mg and Li and the utilization of coatings on the SiC reinforcements with metals (Si, Cu) or oxides [8][9][10][11][12]. The use of SiO 2 became trendy in the last years, particularly as a layer on the SiC reinforcements formed by artificial pre-oxidation [12][13][14][15][16]. More recent reports include the formation SiO 2 layer by the sol-gel route [17,18] and even the use of SiO 2 particles into the SiC preforms [19].…”