Production of Silicon Carbide Particulate Reinforced Aluminium Composite Using Indigenous Stir Casting Technology

Aims: In this research work the viability of producing silicon carbide reinforced aluminium composite using indigenous casting technology has been investigated.

Place and Duration of Study: AfDB Lab, African University of Science and Technology, Abuja between August 2018 and September 2019.

Methodology: The materials used are aluminum alloy 6063 of the following composition: Al -98.5%, Mg -0.51%, Si-0.46%, silicon carbide of particle size 30 µm, and sodium tetra borate (borax) as a wetting agent. In order to produce the composite, the following steps were taken: 6%, 9%, 12%, and 15% volume fractions of Silicon carbide of 1 kg, 1.2kg, 1.5 kg, and 1.6 kg respectively of aluminium alloy 6063 ingots were weighed and preheated to 450°C with simultaneous dehydration of the borax at 250°C. The alloy 6063 was charged into the diesel fire furnace, heated above the liquidus at 750±50°C and then the temperature was allowed to drop to the semi-solid state at about 600°C. The preheated Silicon carbide and dehydrated borax mixture was charge in the ratio 2:1 into the semi-solid alloy and was manually stirred using a preheated stirrer. The composite temperature was raised back to above the liquidus at 750±50°C and automatic stirring was done for 10 minutes using an electric motor with a speed of 300rpm. The molten composite at about 700°C was poured into a green sand mold with graphite coated cavities and the composites solidified into a trapezoidal cross-sectional bar.

Results: It was observed that in terms of weight there is practically little or no difference between the indigenously produced composite and the ones produced by standard technology. The hardness properties of the composite increases with increase in the volume percent of silicon carbide.

Conclusion: Diesel fired crucible furnace can be used to produce quality aluminium silicon carbide composite from locally sourced materials and equipment.