Abstract:
The research investigated the effects of particle size on mechanical, thermal and corrosion behaviour of Quarry Dust (QD) reinforced Aluminium 6063 composites. Double stir casting process was used to produce the composites with particle size of the quarry dust being A (-30+45) μm, B (-45+60) μm, C (-60+75) μm and D (-75) μm. Mechanical characterization, thermal and corrosion behaviours were used to assess the performance of the composites and compared with the unreinforced Aluminium 6063 alloy. The results showed that the hardness of the Aluminium composites improved generally over the unreinforced alloy and decrease with increasing particle size. Sample A with (-30+45) μm had the highest ultimate tensile strength and the strength was seen to decrease marginally as the particle size increases. Sample A had the highest impact energy and dropped as the particle size increases which may be due to the particle cracking of the produced composites. Thermal conductivity was evaluated for unreinforced alloy and the composites and were found to increase with increasing temperature. However, the thermal conductivity for the unreinforced alloy was higher than that of the composites. The thermal conductivity also decreases with increasing particle size. The result of the potentiodynamic study conducted also shows that, the composites, when immersed in 3.5 weight% NaCl environment, the sample A (-30+45) μm becomes less prone to corrosion attack due to the formation of passive films on the surface of the sample and also due to the least value of its corrosion rate of 0.060087 mmpy, which justifies that the quarry dust had no consequential effect on the corrosion resistance of the produced composites in saline environment. The addition of quarry dust to Al6063 alloy shifted the Ecorr downwards, depicting that the quarry dust can be utilized to inhibit Al 6063 in 0.5M H2SO4 environment. However, the highest resistance of the dissociation of Al 6063 composite system was observed in composite sample D (-75) μm in acidic environment having the least corrosion rate of 3.4938 mm/year with corrosion current density of 320.99 A/cm2 due to the thickly rich pearlite phase present in sample D. The results from the research shows that the use of quarry dust as a single reinforcement do not jeopardize the integrity of the material most especially in saline environment
