FACULTY OF TECHNOLOGY
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Item Taguchi optimization of process parameters on the hardness and impact energy of aluminium alloy sand castings(2013) Oji, J. O.; Sunday, P. H.; Petinrin, O. M.; Adetunji, A. R.An optimization technique for sand casting process parameters based on the Taguchi method is reported in this paper. While keeping other casting parameters constant, aluminium alloy castings were prepared by sand casting technique using three different parameters, namely the mould temperature, pouring temperature and runner size. Hardness and impact energy tests were done for the resulted castings. The settings of parameters were determined by using the Taguchi experimental design method. The level of importance of the parameters on the hardness impact energy was determined using the analysis of variance (ANOVA). The optimum parameter combination was obtained by using the analysis of signal-to-noise (S/N) ratio. Analysis of the results shows that 100°C mould temperature and 700°C pouring temperatures are optimal values for hardness and impact energy. However 200 mm2 and 285 mm2 runner sizes are the optimal values for hardness and impact energy respectively. The mould temperature was the most influential parameter on the hardness impact energy of the castings.Item Corrosion protection by novel conversion coatings on structural AI 6061(2022) Oki, M.; Adediran, A. A.; Ikechukwu, A.; Onokohwomo, C. O.; Bosa, C.; Akintola, S. A.; Adesina, O. S.Chromate conversion coatings have witnessed limited acceptability in recent times. The coatings contain Cr (VI) species that have been classified as environmental hazards and injurious to human. Thus, the use of environment-friendly and non-carcinigenic novel inorganic- inorganic hybrid conversion coatings are being explored. Vanadate (VCC), hybrid Vanadate/Molydate (HCC) conversion coatings on A16061 have been classified in terms of corrosion and adhesion performance with reference to the untreated alloy. Natural exposure tests in the atmosphere and stanant near-neutral 3.5% sodium chloride solution, as well as patentio-dynamic polarization measurements showed that the corrosion rate for HCC is lower for Vanadate, which in turn outclassed the ‘bare’ alloy. However, clusters of passive incipient pits were revealed on the former after 120 h of exposure in stagnant chloride solution. Both conversion coatings outperformed the untreated aluminiun alloy after atmospheric corrosion and adhesion tests.Item The effect of A5TB refiner on the fatigue strength of 6063Al alloy(2010) Ibitoye, S. A.; Adeleke, A. A.; Oluwole, O. O.; Tiamiyu, A. O.; Ode, E. BThe study focuses on the influence of aluminium titantium boron (ASTB) master alloy on the fatigue behaviour at 6063Al alloy. Cylindrical cast rods of 6063Al containing different proportions of A5TB ranging from 0-0.11 wt% were produced and were machined to conform to a standard fatigue specimen. The test specimens prepared were tested for fatique strength at various stress levels, and results obtained were compared. The resistance to fatique failure was observed to decrease as the stress level increased. It was also noted that irrespective of stress level, the optimum fatique strength was obtained when the A5TB content was about 0.06 wt%. It was found that 6063Al alloy to which A5TB master alloy have been added was most suitable for the design of components meant to operate under cyclic loading at low stresses below about 3.02KN/m2.