Faculty of Engineering

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    Electrochemical Studies of the Corrosion Behavior of Al/SiC/PKSA Hybrid Composites in 3.5% NaCl Solution
    (MDPI, 2022-09-30) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Olanrewaju Adesina; Peter Omoniyi; Esther Akinlabi
    The corrosion behavior of metal matrix composites (MMCs) is accelerated by the inclusion of reinforcements. Hence, this study investigates the corrosion behavior of MMCs produced from Al 6063 matrix alloy with reinforcement particulates of silicon carbide (SiC) and palm kernel shell ash (PKSA) inclusion at different mix ratios. The MMCs were synthesized using the double stir casting technique. The corrosion behaviors of the composites in NaCl solutions were studied via gravimetric analysis and electrochemical measurements. The gravimetric analysis showed fluctuating dissolution rate of the samples in NaCl solution to indicate flawed film as well as corrosion product formation over the surface of the specimens. The observed corrosion mechanism of the samples was general and pitting corrosion. The presence of reinforcements within the Al6063 matrix acted as active sites for corrosion initiation. The range of values for Ecorr and Icorr obtained in 3.5% NaCl at 24 h was between −220.62 and −899.46 mV and between 5.45 and 40.87 µA/cm2, respectively, while at 72 h, the Ecorr values ranged from 255.88 to −887.28 mV, and the Icorr ranged from 7.19 to 16.85 µA/cm2. The Nyquist and Bode plots revealed the electrochemical corrosion behavior of the samples under investigation, with predominant reactions on the surface of the samples linked to charge transfer processes. The relative resistance to corrosion of the samples depends on the thin oxide film formed on the surface of the samples.
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    Effect of Heat Treatment on Micro Hardness and Microstructural Properties of Al 6063 Alloy Reinforced with Silver Nanoparticles (AgNps)
    (IOP Publishing, 2021-04-27) T.M. Azeez; L. O. Mudashiru; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; O.O. Agboola; Olanrewaju Seun Adesina
    The demand for light weight metals in engineering design has led to the increasing use of aluminum and its alloys. However, conventional high-strength casting aluminum alloys usually exhibit low ductility and toughness, as a result of boundary segregation and coarse dendritic grains which result in its limited application in large-sized and complex shaped work pieces. Also, the possession of a significant low resistance to corrosion of Al 6063 alloys has been a major challenge in applications involving acidic and alkaline media. In this study, silver nano-particle was extracted from a fixer solution. Al 6063 was impregnated with silver Nano-particle at different percentage ratio to form a metal matrix nano composite and the Hardening heat treatment of the reinforced metal matrix nano composite was performed. The elemental composition of Al 6063 prepared from scrap was determined using Light Emission Polyvac Spectrometer. The hardness and microstructural analyses of the composites were evaluated. The micro hardness of the composites was positively influenced by the addition of AgNps and the hardening heat treatment process it was subjected to. The percentage increase in micro hardness of the sample not heat treated but impregnated with 3% and 9% weight nano particles are 20% and 22% respectively. Subjecting these samples to heat treatment further increased the micro hardness to 33% and 37% respectively. The morphology of the composites revealed reasonably homogenous distribution of the reinforcement in the matrix of Al 6063 alloy. It can be concluded that both percentage increase in weight fraction of AgNps and hardening has significantly increased the micro hardness and refined the grain morphology of the Al-AgNps composites.
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    Effect of copper addition and solution heat treatment on the mechanical properties of aluminum alloy using formulated bio-quenchant oils
    (Engineering and Applied Science Research, 2020-01-01) Adekunle A.S.; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Omoniyi P. O.; Gbadamosi T. A.; Jamiu Kolawole Odusote
    Addition of copper and use of solution heat treatment solution with bio degradable vegetable oils as quenchants has great potential to improve the mechanical properties of aluminum and its alloys. In this study, copper was added to as-received Al- Si-Mg alloy to produce Al-Si-Cu-Mg alloy. The specimens were quenched with blended bleached bio-quenchant oils and a petroleum-based oil after solution heat treatment. The alloy was heat treated at 500℃, soaked for 20 minutes in a muffle furnace before quenching in the formulated bio-quenchant oils. The cooling properties, mechanical properties and microstructure of the solution treated specimens were determined. Blended bleached melon (BBM) oil was observed to have offered a higher cooling rate of 49.3 ℃ s-1 compared to the petroleum-based (PB) oil with a cooling rate of 25.8 ℃ s-1. Blended bleached melon oil exhibited the highest quench severity value of 1.0074 m-1, while petroleum-based oil was 0.6133 m-1. The as-received alloy and as-cast alloy specimens exhibited tensile strength values of 125.33 and 131.37 N mm-2, respectively, while a higher tensile strength value of 139.30 Nmm-2 was obtained using the blended bleached melon oil. The highest Rockwell hardness number, 61.00 HRB, was obtained using blended bleached melon oil. The overall mechanical properties of specimens improved after the addition of copper and heat treatment in various bio-quenchant oils
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    Mechanical properties and microstructural evaluation of heat-treated aluminum alloy using formulated bio-quenchants
    (Akademiai Kiado, 2020-10-03) A. S. Adekunle; Tajudeen Adelani Gbadamosi; P.O. Omoniyi; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Jamiu Kolawole Odusote
    Heat treatment industries require various quenching media to improve the properties of the materials to be quenched. Petroleum based mineral (PBM) oil, a non-biodegradable oil, is popular amongst others quenchants in heat treatment processes. Recently, biodegradable oils mostly in their raw, unblended and unbleached forms have been employed for quenching of various engineering materials. Therefore, the present study examined the effects of some selected bio-quenchants in blended raw (BR) and blended bleached (BB) forms on the mechanical properties and microstructure of solution heat treated aluminum (Al)-alloy. Edible vegetable oil (70% by volume) was blended with 30% by volume of jatropha oil to form the bio-quenchant oils. Another set of bio-quenchants were formed by bleaching the raw oils before mixing so as to reduce the oxidation level and contaminations in the oil. The Al-alloy is solution heat treated at 500 °C and soaked for 15 min in an electric muffle furnace before quenching in the various established bio-quenchants. Results showed that samples treated in blended raw melon (BRM) oil have higher tensile strength of 151.76 N/mm while samples quenched in blended bleached melon (BBM) oil have higher hardness value of 61.00 HRC. In accordance to the results obtained the bio-quenchants were found to be effective replacement to the PBM oil.