Department of Metallurgical and Materials Engineering

Permanent URI for this community

https://ir.unilag.edu.ng/handle/123456789/3477

Browse

Browsing Department of Metallurgical and Materials Engineering by Author "Adeosun, S.O."

Now showing 1 - 20 of 73
  • Item
    Open Access
    Acetylation, crystalline and morphological properties of structural polysaccharide from shrimp exoskeleton
    (Engineering Science and Technology, an International Journal, 2017) Gbenebor, O.P.; Adeosun, S.O.; Lawal, G.I.; Olaleye, S.A.
    The extraction of a structural polysaccharide, a-chitin, from shrimp exoskeleton via chemical means using hydrochloric acid (HCl) and sodium hydroxide (NaOH) has been done. Concentrations of 0.4, 0.8 and 1.2 M for both HCl and NaOH were chosen to evaluate the acetylation degree (DA), crystalline structure and morphology of the chitin. The N-acetyl groups’ content in the structural polysaccharide ranged between 65.6 and 99.4% in decreasing order of both acid and alkali concentrations combination used. The magnitude of chitin average hydrogen bond energy EH was majorly influenced by OH(6). . .OC intra and CO. . .HN intermolecular hydrogen bonds as they showed more predominance than OH(3). . .O(5) and OH. . .OC intra and intermolecular hydrogen bonds. Chitin diffraction planes, crystalline index (Crl) and crystallite size (Dhkl) were investigated by X-ray diffraction (XRD) with reflections observed on (021), (110), (130) and (013) planes. The Crl occurred between 79.4 and 87.4%, while crystallite sizes were between 0.544 and 3.64 Å for the samples. Morphological study using scanning electron microscopy with energy dispersive spectroscopy SEM/EDS showed strong calcium and oxygen peaks. This established the shrimp shell surface to be composed of calcite and trace elements such as nitrogen and silicon. The observed a-chitin rough surfaces were attributed to the low degree deacetylation recorded during alkali treatment.
  • Item
    Open Access
    Analysing wear behaviour of Al–CaCO3 composites using ANN and Sugeno-type fuzzy inference systems
    (Neural Computing and Applications, 2020) Sosimi, A.A.; Gbenebor, O.P.; Oyerinde, O.; Bakare, O.O.; Adeosun, S.O.; Olaleye, S.A.
    Design of experiment for the development of stir cast calcium carbonate-reinforced aluminium composite is a search for optimum combination of material and process control parameters for best physical and mechanical properties. A softcomputing model can accurately learn the complex interactions between process parameters to provide great insights in the development of this composite. This paper demonstrates and analyses the potential of artificial neural network (ANN) and Sugeno-type fuzzy inference systems (FIS) for wear behaviour prediction of calcium carbonate-reinforced aluminium composites. The models were trained with data collected from the experiment. The data consist of filler particle size of 150 lm with weights fractions varied from 0 to 25 wt%, in step of 5. Wear test data at different time of contacts (30, 60, 90, 120 and 150 s) and variable loads of 2.27 N, 4.54 N and 6.80 N were collected, resulting to 120 length vectors. Comparing the experimental results of wear test with those predicted using the ANN and Sugeno-type FIS, the integration of calcium carbonate particulate enhanced the wear characteristics of Al matrix up to 200%. On the use of backpropagation neural network with 4–3–1 architecture for wear prediction, the Levenberg–Marquardt training algorithm performs better. For Sugeno-type FIS, the Gaussian membership function resulted to the best prediction of wear rate. When ANN and Sugeno-type FIS performance on the test set were analysed based on some statistical parameters, the later returned an R2 value of 0.9775 as against ANN’s value of 0.3684. The predicted wear rate using ANFIS with Gaussian membership functions was in good agreement with the experimental values.
  • Item
    Open Access
    Anisotropic responses of mechanical and thermal processed cast Al-Si-Mg-Cu Alloy
    (The Minerals, Metals & Materials Society, 2015) Adeosun, S.O.; Akpan, E.I.; Balogun, S.A.; Onoyemi, O.K.
    The effects of ambient directional rolling and heat treatments on ultimate tensile strength (UTS), hardness (HD), percent elongation (PE), and impact energy (IE) on Al-Si-Mg-Cu alloy casting with reference to inclination to rolling direction are discussed in this article. The results show that rolled and quenched (CQ) sample possess superior UTS and HD to as-cast and those of rolled and aged samples (CA). Improved IE resistance with ductility is shown by both CQ and CA samples. However, these mechanical properties are enhanced as changes in the test sample direction moved away from rolling direction for all heat-treated samples. The CQ samples displayed highest tensile strength (108 MPa) and PE (19.8%) in the 90 direction.
  • Item
    Open Access
    Characteristics of aluminum hybrid composites
    (World Academy of Science, Engineering and Technology International Journal of Chemical, Nuclear, Metallurgical and Materials Engineering, 2014) Adeosun, S.O.; Osoba, L.O.; Taiwo, O.O.
    Aluminum hybrid reinforcement technology is a response to the dynamic ever increasing service requirements of such industries as transportation, aerospace, automobile, marine, etc. It is unique in that it offers a platform of almost unending combinations of materials to produce various hybrid composites. This article reviews the studies carried out on various combinations of aluminum hybrid composite and the effects on mechanical, physical and chemical properties. It is observed that the extent of enhancement of these properties of hybrid composites is strongly dependent on the nature of the reinforcement, its hardness, particle size, volume fraction, uniformity of dispersion within the matrix and the method of hybrid production.
  • Item
    Open Access
    Characteristics of Aluminum Hybrid Composites
    (International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering, 2014) Adeosun, S.O.; Osoba, L.O.; Taiwo, O.O.
    Aluminum hybrid reinforcement technology is a response to the dynamic ever increasing service requirements of such industries as transportation, aerospace, automobile, marine, etc. It is unique in that it offers a platform of almost unending combinations of materials to produce various hybrid composites. This article reviews the studies carried out on various combinations of aluminum hybrid composite and the effects on mechanical, physical and chemical properties. It is observed that the extent of enhancement of these properties of hybrid composites is strongly dependent on the nature of the reinforcement, its hardness, particle size, volume fraction, uniformity of dispersion within the matrix and the method of hybrid production.
  • Item
    Open Access
    Characteristics of biodegradable implants
    (Journal of Minerals and Materials Characterization and Engineering, 2014, 2014) Adeosun, S.O.; Lawal, G.I.; Gbenebor, O.P.
    The development of synthetic biomaterials for bone fixations has greatly enhanced orthopedic surgery efficiency over the last two decades. With the advancement in medical technology, several materials such as metals, ceramics, polymers and composites have been considered over the years for possible implantation into the body. These materials however, must have the following required properties that will qualify them as potential medical devices: biocompatibility, mechanical properties, corrosion resistance, creep resistance, etc. The quest in making up for the disadvantages of metallic fixations has culminated in a paradigm shift to the use of biodegradable polymers. Biodegradable polymers are light-weight materials with low elastic moduli between 0.4 - 7 GPa. These materials can be engineered to degrade at rates that will slowly transfer load to the bone. In addition, complications like corrosion, release of metal ions and stress shielding associated with metal implants are eliminated. This review considers studies carried out on most commonly investigated and widely used synthetic biodegradable polymers, their successes and limitations. It also provides process for efficient utilization of these polymers as bone fixtures without inflammation and stress shielding.
  • Item
    Open Access
    Characterization of adhesion surface of cellulosic fibers extracted from agro wastes
    (Journal of Natural Fibers, 2016) Akpan, E.I.; Adeosun, S.O.; Lawal, G.I.; Balogun, S.A.; Chen, D.I.
    The adhesion characteristics of agro waste–derived fibers are examined in this study. Fibers obtained from groundnut shell, coconut shell, rice husk, palm fruit bunch, and palm fruit stalk are subjected to a combination of batch treatments in two distinctive ways. These batch fiber treatments involve mechanical defibrillation, steam explosion, acid hydrolysis, alkaline hydrolysis, and enzymatic hydrolysis. Topography, mean surface roughness, maximum surface roughness, skewness, and morphology of the resulting fibers are characterized using the atomic force microscopy and scanning electron microscopy. Results show that the treatments are effective in removal of noncellulosic materials and smoothening of fiber surface. This phenomenon would results in improvement in wettability between fiber and matrix in polymer composite applications. Palm fruit–derived fibers are found to retain a greater portion of noncellulosic materials compared to others. This is attributed to the high amorphous content of palm fruit with very low crystalline portion compared to others.
  • Item
    Open Access
    Characterization of LDPE reinforced with calcium carbonate—fly ash hybrid filler
    (Journal of Minerals and Materials Characterization and Engineering, 2014) Adeosun, S.O.; Usman, M.A.; Akpan, E.I.; Dibie, W.I.
    The synergetic effect of calcium carbonate (CC)-fly ash (FA) hybrid filler particles on the mechanical and physical properties of low density polyethylene (LDPE) has been investigated. Low density polyethylene is filled with varying weight percentages of FA and CC using melt casting. Composites are characterized for mechanical, thermal, microstructural and physical properties. Results show that the flexural strength increases with increases in FA content of the hybrid filler. It is evident from the study that to achieve optimum density a certain combination of both fillers need to be used. The optimum combination of CC and FA for a higher density (1.78 g/cm3) is found to be at 20 wt% FA and 30 wt% CC. An increase of 7.27% in micro-hardness over virgin polyethylene is obtained in composites with 10 wt% FA and 40 wt% CC. The presence of higher amount of CC is seen to be detrimental to the crystallinity of composites. X-ray, FTIR and DSC results show that composite with 45 wt% CC and 5 wt% FA exhibits a typical triclinic polyethylene structure indicating that the composite is amorphous in nature. There was the synergy between FA and CC fillers on flexural strength and crystallinity of composite. However, the fillers show the antagonistic effect on energy at peak and micro-hardness.
  • Item
    Open Access
    Combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy
    (2014) Adeosun, S.O.; Sekunowo, O.I.; Talabi, S.I.
    This study investigated the combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy. Samples of the alloy are cast in metal mould to obtain 0.94- 2.19wt% mixes of titanium. These samples are grouped into untreated (as-cast) and those that are cold rolled to fifty percent reduction, homogenized at 5000C and soaked for one hour. The cold rolled and heat treated samples are normalized (RTn) and quenchtempered (RTq-t) at 1000C. All these samples are subjected to tensile, micro-hardness and microstructural evaluation. Results show remarkable improvement in the mechanical properties of the cold rolled and heat treated samples compared to the as-cast. In particular, the RTq-t samples containing titanium in the range of 1.7-2.2% demonstrates improve tensile strength by 24.7%, yield strength, 28%, elastic modulus, 38.3% and micro-hardness, 20.5%. The Al3Ti phase being the most stable precipitate in the α-Al matrix appears to have been responsible for the significant improvement in the alloy’s mechanical properties. It is concluded that quench and temper heat treatment is an effective method of improving the strength-strain ratio of cold rolled Al-.0.9-2.2%Ti alloy.
  • Item
    Open Access
    Comparative effects of organic and inorganic bio-fillers on the hydrophobicity of polylactic acid
    (Results in Engineering, 2020) Aworinde, A.K.; Adeosun, S.O.; Oyawale, F.A.; Akinlabi, E.T.; Akinlabi, S.A.
    The use of Polylactic acid (PLA) has been limited in the biomedical field because of its slow degradation profile which is traceable to its degree of hydrophobicity. In this work, 16.67 wt. % of chitosan (Ch), chitin (Ct) and titanium (Ti-6Al-2Sn-2Mo-2Cr-0.25Si) (Ti) powders weremelt blended with PLA and the resulting composites examined using Fourier Transform Infrared Spectroscopy (FTIR). Chitosan was found to reduce the hydrophobic peak due to δs(CH3) in PLA by 13.92%, chitin by 10.65% and titanium by 8.04%. Summarily, the organic biofillers produced more hydrophilic PLA composites than the inorganic filler. The percentage reduction in hydrophobicity renders the developed composites more suitable for orthopaedic applications.
  • Item
    Open Access
    Comparative effects of organic and inorganic bio-fillers on the hydrophobicity of polylactic acid
    (Results in Engineering, 2020) Aworinde, A.K.; Adeosun, S.O.; Oyawale, F.A.; Akinlabi, E.T.; Akinlabi, S.A.
    The use of Polylactic acid (PLA) has been limited in the biomedical field because of its slow degradation profile which is traceable to its degree of hydrophobicity. In this work, 16.67 wt. % of chitosan (Ch), chitin (Ct) and titanium (Ti-6Al-2Sn-2Mo-2Cr-0.25Si) (Ti) powders weremelt blended with PLA and the resulting composites examined using Fourier Transform Infrared Spectroscopy (FTIR). Chitosan was found to reduce the hydrophobic peak due to δs(CH3) in PLA by 13.92%, chitin by 10.65% and titanium by 8.04%. Summarily, the organic biofillers produced more hydrophilic PLA composites than the inorganic filler. The percentage reduction in hydrophobicity renders the developed composites more suitable for orthopaedic applications.
  • Item
    Open Access
    Corrosion Behaviour of Heat-Treated Aluminum-Magnesium Alloy in Chloride and EXCO Environments
    (Hindawi Publishing Corporation International Journal of Corrosion, 2012) Adeosun, S.O.; Balogun, S.A.; Obiekea, V.D.; Sekunowo, O.I.
    Machines designed to operate in marine environment are generally vulnerable to failure by corrosion. It is therefore imperative that the corrosion susceptibility of such facilities is evaluated with a view to establishing mechanism for its mitigation. In this study, the corrosion behaviour of as-cast and retrogression-reagion (RRA) specimens of aluminum alloy containing 0.4–2.0 percent magnesium additions in NaCl, FeCl3, and EXCO solutions was investigated. The corrosion simulation processes involved gravimetric and electrochemical techniques. Results show substantial inducement of Mg2Si precipitates at a relatively higher magnesium addition, 1.2–2.0 percent, giving rise to increased attack. This phenomenon is predicated on the nature of the Mg2Si crystals being anodic relative to the alloy matrix which easily dissolved under attack by chemical constituents. Formation of Mg2Si intermetallic without corresponding appropriate oxides like SiO2 and MgO, which protect the precipitates from galvanic coupling with the matrix, accentuates susceptibility to corrosion.
  • Item
    Open Access
    Cracking susceptibility after post-weld heat treatment in haynes 282 nickel based superalloy
    (ACTA Metallurgica Sinica, 2013) Osoba, L.O.; Khan, A.K.; Adeosun, S.O.
    This paper presents a study of the standard post-weld heat treatment (PWHT) behaviour of autogenous laser welded γ’ age-hardenable precipitation strengthened nickel based superalloy Haynes 282 (HY 282). The study involves a careful and detailed microstructural characterisation as well as an analysis of the weld cracking susceptibility during welding and Gleeble thermo-mechanical physical simulation. Various factors that could influence post-weld cracking in superalloys weld were experimentally examined. Our microstructural examination of the as-solution heat treated (SHTed) material and the thermo-mechanically refined grain material shows that intergranular heat affected zone (HAZ) cracking is observable in only the as-welded SHTed material. There was no indication of post-weld heat treatment cracking in all welded materials. Our conclusion, in this study, is that the chemistry of superalloy HY 282 which aids the preclusion/ formation of deleterious solidification microconstituents during welding as well as its relatively slow aging kinetics enhances its resistance to PWHT cracking.
  • Item
    Open Access
    Cracking Susceptibility After Post-Weld Heat Treatment in Haynes 282 Nickel Based Superalloy
    (Acta Metall. Sin. (Engl. Lett.), 2013) Osoba, L.O.; Khan, A.K.; Adeosun, S.O.
    This paper presents a study of the standard post-weld heat treatment (PWHT) behaviour of autogenous laser welded γ’ age-hardenable precipitation strengthened nickel based superalloy Haynes 282 (HY 282). The study involves a careful and detailed microstructural characterisation as well as an analysis of the weld cracking susceptibility during welding and Gleeble thermo-mechanical physical simulation. Various factors that could influence post-weld cracking in superalloys weld were experimentally examined. Our microstructural examination of the as-solution heat treated (SHTed) material and the thermo-mechanically refined grain material shows that intergranular heat affected zone (HAZ) cracking is observable in only the as-welded SHTed material. There was no indication of post-weld heat treatment cracking in all welded materials. Our conclusion, in this study, is that the chemistry of superalloy HY 282 which aids the preclusion/ formation of deleterious solidification microconstituents during welding as well as its relatively slow aging kinetics enhances its resistance to PWHT cracking.
  • Item
    Open Access
    Determining Thermal Characteristics of an Oil-Fired Crucible Furnace Using Clay and Alumina Bricks
    (JOURNAL OF THE ASSOCIATION OF PROFESSIONAL ENGINEERS OF TRINIDAD & TOBAGO, 2020) Owolabi, O.B.; Osoba, L.O.; Adeosun, S.O.
    This paper explores the results of an experimental study that was intended to determine the thermal characteristics of an oil-fired crucible furnace using clay and alumina bricks. For the study, a refractory with 0.03118m3 combustion chamber capacity was used. The bricks analysis were carried out under transient condition that would be appropriate for laboratory and workshop with a capacity to reach 950oC within 20 minutes for aluminum and nonferrous scrap re-melting. The performance of the furnace was evaluated, and the results showed that the furnace can operate at a heating rate of 49.44°C/min, with a 29.70% efficiency determined, and which was within the efficiency range of conventional furnace. The heat transfer coefficient of 4.48W/m2K was obtained. Alumina bricks used in lining the furnace was attributable to its higher refractoriness. It was found that a better thermal shock was proved than clay bricks from the Comparative analysis simulation using commercial software ANSYS 14.0 aimed towards improving service life and efficiency.
  • Item
    Open Access
    Determining Thermal Characteristics of an Oil-Fired Crucible Furnace Using Clay and Alumina Bricks
    (The Journal of the Association of Professional Engineers of Trinidad and Tobago, 2020) Owolabi, O.B.; Osoba, L.O.; Adeosun, S.O.
    This paper explores the results of an experimental study that was intended to determine the thermal characteristics of an oil-fired crucible furnace using clay and alumina bricks. For the study, a refractory with 0.03118m3 combustion chamber capacity was used. The bricks analysis were carried out under transient condition that would be appropriate for laboratory and workshop with a capacity to reach 950oC within 20 minutes for aluminum and nonferrous scrap re-melting. The performance of the furnace was evaluated, and the results showed that the furnace can operate at a heating rate of 49.44°C/min, with a 29.70% efficiency determined, and which was within the efficiency range of conventional furnace. The heat transfer coefficient of 4.48W/m2K was obtained. Alumina bricks used in lining the furnace was attributable to its higher refractoriness. It was found that a better thermal shock was proved than clay bricks from the Comparative analysis simulation using commercial software ANSYS 14.0 aimed towards improving service life and efficiency.
  • Item
    Open Access
    Determining Thermal Characteristics of an Oil-Fired Crucible Furnace Using Clay and Alumina Bricks
    (The Journal of the Association of Professional Engineers of Trinidad and Tobago, 2020) Owolabi, O.B.; Osoba, L.O.; Adeosun, S.O.
    This paper explores the results of an experimental study that was intended to determine the thermal characteristics of an oil-fired crucible furnace using clay and alumina bricks. For the study, a refractory with 0.03118m3 combustion chamber capacity was used. The bricks analysis were carried out under transient condition that would be appropriate for laboratory and workshop with a capacity to reach 950oC within 20 minutes for aluminum and nonferrous scrap re-melting. The performance of the furnace was evaluated, and the results showed that the furnace can operate at a heating rate of 49.44°C/min, with a 29.70% efficiency determined, and which was within the efficiency range of conventional furnace. The heat transfer coefficient of 4.48W/m2K was obtained. Alumina bricks used in lining the furnace was attributable to its higher refractoriness. It was found that a better thermal shock was proved than clay bricks from the Comparative analysis simulation using commercial software ANSYS 14.0 aimed towards improving service life and efficiency
  • Item
    Open Access
    Determining Thermal Characteristics of an Oil-Fired Crucible Furnace Using Clay and Alumina Bricks
    (The Journal of the Association of Professional Engineers of Trinidad and Tobago, 2020) Owolabi, O.B.; Osoba, L.O.; Adeosun, S.O.
    This paper explores the results of an experimental study that was intended to determine the thermal characteristics of an oil-fired crucible furnace using clay and alumina bricks. For the study, a refractory with 0.03118m3 combustion chamber capacity was used. The bricks analysis were carried out under transient condition that would be appropriate for laboratory and workshop with a capacity to reach 950oC within 20 minutes for aluminum and nonferrous scrap re-melting. The performance of the furnace was evaluated, and the results showed that the furnace can operate at a heating rate of 49.44°C/min, with a 29.70% efficiency determined, and which was within the efficiency range of conventional furnace. The heat transfer coefficient of 4.48W/m2K was obtained. Alumina bricks used in lining the furnace was attributable to its higher refractoriness. It was found that a better thermal shock was proved than clay bricks from the Comparative analysis simulation using commercial software ANSYS 14.0 aimed towards improving service life and efficiency.
  • Item
    Open Access
    Development and characterization of collagen‑based electrospun scaffolds containing silver sulphadiazine and Aspalathus linearis extract for potential wound healing applications
    (SN Applied Sciences, 2020) Ilomuanya, M.O.; Adebona, A.C.; Wang, W.; Sowemimo, A.; Eziegbo, C.L.; Silva, B.O.; Adeosun, S.O.; Joubert, E.; Beer, D.D.
    Bone, skin and soft tissue chronic wounds emanating from burns or bacterial infections which persist due to prolonged tissue inflammation contribute to a delay in wound healing. Electrospun biomimetic scaffolds produced from biodegradable polymers have proven to be a better alternative due to their large surface area to volume ratio and ability to release the drug directly to the wound surface allowing fast and sustained absorbance over the affected wound area. In this study, poly lactic acid (PLA) (20% w/v) and collagen-based (PLA/C) fibrous scaffolds (electrospun at a voltage of 22 kV, flow rate of 0.1 mL/min) containing varying concentrations of silver sulphadiazine (1% w/w, 0.75% w/w) (Ag+S) and Aspalathus linearis (AL) fermented extract (0.025%, 0.1% and 0.5% w/w), were designed and fabricated to increase antimicrobial penetration and cellular biocompatibility. The elastic modulus of samples revealed that incorporating 1% Ag+S and A. linearis extract to PLA solution culminates in a fiber with the superlative stiffness of 2.1.1 GPa. The antimicrobial effect of the scaffolds was evaluated against S. aureus, P. aeruginosa, MRSA and E. coli. PLA/C–Ag+S/AL scaffolds and showed antibacterial activity against both gram +ve and gram −ve bacteria. They were nontoxic to the cells and provided favorable substrates for the neonatal epidermal keratinocytes cells to undergo cell attachment and proliferation. PLA/C– Ag+S/AL scaffolds have a great potential for use in chronic wounds as well as in tissue and bioengineering applications.
  • Item
    Open Access
    Development and characterization of collagen‑based electrospun scaffolds containing silver sulphadiazine and Aspalathus linearis extract for potential wound healing applications
    (SN Applied Sciences, 2020) Ilomuanya, M.O.; Adebona, A.C.; Wang, W.; Sowemimo, A.; Eziegbo, C.L.; Silva, B.O.; Adeosun, S.O.; Joubert, E.; Beer, D.D.