Morphology of Al-2.5%Mg/xSiCp Composite developed by Stir Casting Process

Abstract

. The research was conducted to enhance and solve the issues associated with low wettability and insufficient bonding between aluminum and silicon carbide that usually associated with stir casting process. The study used magnesium, heat treatment of SiCp and metallic (SiO2) coating on SiCp for improved Al-SiCp wettability in the manufacture of composite. The wt.% of SiCp was varied from 5 wt.% to 20 wt.% (uncoated and coated) at 5 wt.% intervals. The characterization conducted are XRD, XRF and SEM on the samples developed. XRD plots confirmed existence of Al with major peaks at 38.5, 45.11, 65.35, and 78.31; while Mg and SiCp were seen at 34.82 and 60.78 respectively. The XRF analysis revealed that major elements are within the range proposed for research with Alumina contains the highest amount of 70.05 – 86.69 wt.%, followed by Magnesium with 2.46 - 2.57 wt.%, and silicon having varying values of 0.91 wt.% for Sample A, 5.91 – 21.01 wt.% for uncoated samples B – E, and higher values of 8.43 – 24.43 wt.% for Samples F – I compared to the control sample, while all other minerals present are in such negligible proportion. The SEM/EDS results showed a fair dispersion of the SiCp particles in the samples with weight percentages of Al between 54.3 – 72.7 wt.%, Mg with 2.33 wt.% for control sample and a higher of values of 3.90 – 8.22 wt.% for composite samples, and Si with 0.10 – 1.32wt.%. Owning to this best performance test results, the coated Al-2.5%Mg/10wt%SiCp (Sample G) may be adopted as an alternate monolithic alloy to the existing AlMn, AlMg and AlMgSi alloys for structural, heavy machineries and marine applications where light weight is required.