A correlation between nano and micro-hardness properties of TiN nanoparticles strengthened SAF 2205
- Authors: Mphahlele, M. R. , Oke, S. R. , Ige, O. O. , Falodun, O. E. , Obadele, B. A. , Olubambi, P. A. , Shongwe, M. B.
- Date: 2019
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/384466 , http://hdl.handle.net/10210/296599 , uj:32316 , Citation: Mphahlele, M.R. et al. 2019. A correlation between nano and micro-hardness properties of TiN nanoparticles strengthened SAF 2205. IOP Conf. Series: Materials Science and Engineering 499 (2019) 012009 IOP Publishing doi:10.1088/1757-899X/499/1/012009
- Description: Abstract: This work studied the correlation between Vickers and nano-hardness of SAF 2205 reinforced with TiN nanoparticles for the convenience of assessing its mechanical properties. Spark plasma sintering was used to fabricate the composites. Micro and nanoindentations were performed to determine micro and nanohardness values of the fabricated composite. Optical microscope was used to assess the microstructure. The microstructure revealed that the TiN dominated the ferrite/ferrite, ferrite/austenite and austenite/austenite grain boundaries. The micro and nanohardness at the TiN dominated grain boundaries were higher compared to the grain hardness. Hardness also increased considerably as the TiN nanoparticles increases. This is also owed to the strengthening effect played by TiN at the grain boundaries by disrupting dislocation motion in the composite. The determined Vickers hardness was plotted as a function of the corresponding nanohardness, a good linear relation was found between Vickers hardness and nanohardness. A linear relationship (HV = 215.15 + 15.03Hnano) was established which indicates that there is no difference in behavior for the Vickers hardness and nano- hardness.
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A correlation between nano and micro-hardness properties of TiN nanoparticles strengthened SAF 2205
- Authors: Mphahlele, M. R. , Oke, S. R. , Ige, O. O. , Falodun, O. E. , Obadele, B. A. , Olubambi, P. A. , Shongwe, M. B.
- Date: 2019
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/401131 , uj:33510 , Citation: M R Mphahlele et al 2019. A correlation between nano and micro-hardness properties of TiN nanoparticles strengthened SAF 2205.IOP Conf. Ser.: Mater. Sci. Eng. 499 012009
- Description: Abstract: This work studied the correlation between Vickers and nano-hardness of SAF 2205 reinforced with TiN nanoparticles for the convenience of assessing its mechanical properties. Spark plasma sintering was used to fabricate the composites. Micro and nanoindentations were performed to determine micro and nanohardness values of the fabricated composite. Optical microscope was used to assess the microstructure. The microstructure revealed that the TiN dominated the ferrite/ferrite, ferrite/austenite and austenite/austenite grain boundaries. The micro and nanohardness at the TiN dominated grain boundaries were higher compared to the grain hardness. Hardness also increased considerably as the TiN nanoparticles increases. This is also owed to the strengthening effect played by TiN at the grain boundaries by disrupting dislocation motion in the composite. The determined Vickers hardness was plotted as a function of the corresponding nanohardness, a good linear relation was found between Vickers hardness and nanohardness. A linear relationship (HV = 215.15 + 15.03Hnano) was established which indicates that there is no difference in behavior for the Vickers hardness and nano- hardness.
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Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys
- Authors: Babalola, B. J. , Shongwe, M. B. , Obadele, B. A. , Olubambi, P. A. , Ayodele, O. O. , Rominiyi, A. L. , Jeje, S. O.
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/289454 , uj:31406 , Citation: Babalola, B.J. et al. 2018. Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys. MATEC Web of Conferences 249, 0100 (2018) https://doi.org/10.1051/matecconf/20182490100
- Description: Abstract: Spark plasma sintering (SPS) has been widely regarded as an advanced powder consolidation technique which helps in the development of array of engineering materials. Many have been reported in the literature about sintering parameters such as temperature, pressure, heating rate and holding time. However, little or no reports has been made on some of the intricate features such as process time(s), power SPS (KW), pressing speed (mm/min), and average pressing force (KN) on which sintering parameters are directly related to. This study aims to investigate the behaviour of spark plasma sintered Ni-17Cr binary alloys with emphasis on the densification, hardness value and spark plasma sintering features such as process time (s), power SPS (KW), pressing speed (mm/min), and the average pressing force (KN). Nickel and chromium powders were milled individually using High energy ball milling for durations of 5hr, 10 hr prior to mixing and subsequent sintering. The sintered 5 hr and 10 hr milled Ni-17Cr binary alloys attained relative densities of 98.72 % and 99.1 % respectively. The Microstructural morphology was examined using Scanning electron microscopy (SEM). The sintered 10 hr milled Ni-17Cr binary alloy revealed the higher hardness.
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Densification behavior of spark plasma sintered duplex stainless steel reinforced with TiN nanoparticles
- Authors: Oke, S. R. , Ige, O. O. , Falodun, O. E. , Mphahlele, M. R. , Olubambi, P. A.
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/279896 , uj:30067 , Citation: Okel, S.R. et al. 2018. Densification behavior of spark plasma sintered duplex stainless steel reinforced with TiN nanoparticles. IOP Conf. Series: Materials Science and Engineering 430 (2018) 012034 doi:10.1088/1757-899X/430/1/012034 , Citation: Okel, S.R. et al. 2018. Densification behavior of spark plasma sintered duplex stainless steel reinforced with TiN nanoparticles.
- Description: Abstract: Duplex stainless steel (SAF 2205) reinforced with titanium nitride (TiN) nanoparticles ranging from 0 to 8 wt% were fabricated in vacuum via spark plasma sintering (SPS) using optimized SPS process parameter of 1150 oC, 10 min and 100 oC/min. The influence of TiN addition on the densification and shrinkage mechanism of the fabricated duplex stainless steel composite were evaluated. The results indicate even dispersion of the TiN nanoparticles in the steel matrix during tubular mixing. The displacement and shrinkage rates showed three densification stages relating to micro-nano particles rearrangement, plastic deformation of the particles and rapid densification of the composite. The steel composite samples displayed relatively high densities in the range of 96-99 % of the calculated theoretical density but were noted to decrease with TiN content.
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Direct bioleaching of Zinc using manihot esculenta crantz (cassava) extract without additives
- Authors: Ajibola, O. O. , Adebayo, A. O. , Borisade, S. G. , Adegbenro, A. E. , Oloruntoba, D. T. , Olubambi, P. A.
- Date: 2020
- Subjects: Direct bioleaching , Zinc ore , Manihot esculenta Crantz
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/464032 , uj:41434 , Citation: Ajibola, O.O., Adebayo, A.O., Borisade, S.G., Adegbenro, A.E., Oloruntoba, D.T., Olubambi, P. A. (2020). Direct bioleaching of Zinc using manihot esculenta crantz (cassava) extract without additives. Fudma Journal Of Sciences, 4(2), 645 - 657. , DOI: https://d oi.org/10.33003/fjs-2020-0402-199
- Description: Abstract: The advent and development of new technologies that will provide better yields, cleaner and a safer environment is a global challenge for the researchers. Traditional solvents used in extraction of minerals are at many times hazardous thereby constituting threats to the ecology. The work reports the direct bioleaching of zinc sourced from Abakaliki-Ishiagwu complex zinc sulphide ore deposit. The sphalerite ore is predominant in Zn with other associated metals Pb, Cu, Fe, Ni, Sb, As, Cd, Au, V, Co, Ag, K, Al and Ca. It covers the pre extraction processes of mineral comminution (crushing and grinding); separation by froth flotation; and roasting. Agro-cyanide was extracted from cassava plant (Manihot esculenta Crantz) leaves and was used as leachant without any additive. The result of atomic absorption spectrometry (AAS) analysis of the leached liquor (pregnant solution) shows that lead, copper and iron in addition to Zinc, were obtained from the leached ore roast at 149.25 ppm (Zn), 79.25 ppm (Pb), 0.25 ppm (Cu) and 4.25 ppm (Fe) extraction after 21 days. Elongated contact of ZnO ore is not encouraging for Zn extraction as there is a decline in the quantity of Zn, Fe and Cu as the leaching time (days) increases. The mechanism of the Leach next faction is yet to be fully ascertained, hence the need for further work in the area.
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Effect of CrC-Ni on the tribological behaviour of WC cemented carbide
- Authors: Mekgwe, G. N. , Tuckart, W. R. , Akinribide, O. J. , Langa, T. , Obadele, B. A. , Olubambi, P. A.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/405049 , uj:33995 , Citation: Mekgwe, G.N. et al. 2019. Effect of CrC-Ni on the tribological behaviour of WC cemented carbide. IOP Conf. Series: Materials Science and Engineering 499 (2019) 012012. doi:10.1088/1757-899X/499/1/012012
- Description: Abstract. Tungsten carbide (WC) is extensively used in industrial processing as cutting tools, wear resistant components and drilling tools owing to the good combination of phenomenal properties. The binder phase of WC is usually cobalt (Co) as a result of good wetting behaviour and excellent solubility with regards to WC particles. However, degradation of WC-Co components when subjected to harsh environmental conditions often results in premature failures during application. In this study, the effect of CrC-Ni on the microstructure, mechanical and tribological properties of WC based cermet produced by spark plasma sintering was investigated. Sintered samples were then analysed and characterized by SEM and EDS. Macro hardness of the sintered compacts were evaluated using Rockwell hardness machine at 150kg load. Subsequently, comparative studies on the tribological behaviour of the experimental samples were performed using a reciprocating wear set up at 200°C. The area of the wear track cross-section was measured using optical profiler and the wear rate in terms of volume loss was calculated. Results showed improved mechanical and tribological properties on WC-20CrC-7Ni sample as compared to WC-Co cemented carbide sample.
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Effect of graphite addition on the tribological properties of pure titanium carbonitride prepared by spark plasma sintering
- Authors: Mekgwe, G. N. , Akinribide, O. J. , Langa, T. , Obadele, B. A. , Olubambi, P. A. , Lethabane, L. M.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/405065 , uj:33997 , Citation: Mekgwe, G.N. et al. 2019. Effect of graphite addition on the tribological properties of pure titanium carbonitride prepared by spark plasma sintering. IOP Conf. Series: Materials Science and Engineering 499 (2019) 012011. doi:10.1088/1757-899X/499/1/012011
- Description: Abstract: Titanium carbonitride (TiCN) based cermet has received extensive attention as important components substantially utilized in cutting tools, milling operations and in sliding bearings. Recently, conventional WC-Co based hard alloys are being replaced with TiCN based cermets accompanied with the trend of high speed machining. These materials are considered potential candidate for a variety of tribological applications. In this study, the effects of graphite additions on titanium carbonitride (TiCN) based cermet were investigated. This involved consolidation of TiC0.7TiN0.3 composition of pure TiCN based cermet and/with 0.5, 1.0 and 1.5 wt % graphite using spark plasma sintering (SPS). The comparative studies on the tribological behaviours of the TiCN based cermets with graphite additions were performed using ball on disc set up at ambient temperature. Results show that the presence of different composition of graphite influences the microstructures of TiCN. In addition, a change in wear response of the sintered compacts was observed.
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Effect of milling parameters on the dispersion characteristics of multi-walled carbon nanotubes in transition metal oxides
- Authors: Lephuthing, S. S. , Okoro, M. , Lesufi, M. , Ige, O. O. , Olubambi, P. A.
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/279891 , uj:30066 , Citation: Lephuthing, S.S. et al. 2018. Effect of milling parameters on the dispersion characteristics of multi-walled carbon nanotubes in transition metal oxides. IOP Conf. Series: Materials Science and Engineering 430 (2018) 012002 doi:10.1088/1757-899X/430/1/012002
- Description: Abstract: In this research investigation on milling parameters to achieve uniform dispersion of multi-walled carbon nanotubes (MWCNTs) was conducted. High-energy ball milling (HEBM) technique was adopted to disperse 1 wt. % MWCNTs in titanium and manganese oxides with ball to powder ratio (BPR) of 10:1 at 6 and 9 hours milling times. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the as-received MWCNTs and admixed composite powders. The results indicated that HEBM was an effective route to disperse MWCNTs in transition metal oxides. In addition, the characteristics of admixed powders evidently showed that the increase of milling time effectively dispersed the MWCNTs in titanium and manganese oxide respectively, however deformation of sidewalls of MWCNTs was observed due to harsh milling conditions that resulted on non-sp2 defects in the MWCNTs.
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Effect of sintering parameters on the densification and hardness of NiAl-CNTs composite
- Authors: Awotunde, M. A. , Ayodele, O. O. , Adegbenjo, A. O. , Okoro, A. M. , Shongwe, M. B. , Olubambi, P. A.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/405786 , uj:34091 , Citation: Awotunde, M.A. et al. 2019 : Effect of sintering parameters on the densification and hardness of NiAl-CNTs composite. IOP Conf. Series: Materials Science and Engineering 628 (2019) 012007. DOI:10.1088/1757-899X/628/1/012007.
- Description: Abstract : Nickel aluminides have attracted considerable interest in the past few decades owing to its unique properties. In this work, nickel aluminide (NiAl) was formed in-situ during spark plasma sintering of admixed powders of nickel, aluminium and carbon nanotubes (CNTs) after ball milling. 1 wt % CNTs was incorporated into the intermetallic matrix and the effect of varying sintering parameters investigated, particularly the sintering temperature and pressure. Results showed that a combination of higher sintering temperature with lower pressure yielded better results than lower sintering temperature and higher pressure. Thus the former parameters yielded better densification and subsequently higher micro hardness values of the NiAl-CNTs composites as compared to the latter.
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Effects of alloying on aluminium-silicon alloys – a review
- Authors: Joseph, O. O. , Olubambi, P. A. , Joseph, Olakunle O. , Edun, B. M. , Okeniyi, J. O. , Abioye, O. P.
- Date: 2021
- Subjects: Aluminium-silicon , Composition , Properties
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/480119 , uj:43451 , Citation: O.O. Joseph et al 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1107 012116 , DOI: 10.1088/1757-899X/1107/1/012116
- Description: Abstract: Please refer to full text to view abstract.
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Erosion-corrosion behaviour of dual phase medium carbon steel using a designed slurry pot
- Authors: Aribo, S. , Adedapo, I. , Nwogwugwu, C. , Olaniran, O. , Olaseinde, A. , Ige, O. , Olubambi, P. A.
- Date: 2018
- Subjects: Slurry pot , Dual phase steel , Erosion-corrosion
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/279666 , uj:30037 , Citation: Aribo, S. et al. 2018. Erosion-corrosion behaviour of dual phase medium carbon steel using a designed slurry pot. Tribology in Industry, 40(2):239-246, DOI: 10.24874/ti.2018.40.02.07
- Description: Abstract: A slurry pot has been designed, fabricated and evaluated for erosion-corrosion investigations. A variable voltage controller was used to vary the input voltage into the one-horse-power motor that controls the slurry pot. The actual speed of the slurry pot shaft was also calibrated using a non-contact digital tachometer. Voltages of 100 and 200 V resulted in rotational speeds of 1100 and 2100 rpm, respectively employed for the subsequent erosion-corrosion tests. Erosion-corrosion of a dual-phase carbon steel was investigated with the aid of the slurry pot in aerated 3.5 wt.% NaCl environments. The sample was normalised at 850 oC and then cooled in air to room temperature. Prior to the test, the normalised samples were heated to 700, 725, 750, 775, 800 and 825 oC, respectively and quenched in oil. Erosion-corrosion rates of between 0.027 to 1.26 g/cm2.hr at 1100 rpm and 0.57 to 1.9 g/cm2.hr at 2100 rpm were recorded. It was also observed that as hardness increased there was reduction in weight loss of the heat treated alloy.
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Improving mechanical and thermal properties of graphite–aluminium composite using Si, SiC and eggshell particles
- Authors: Durowoju, M. O. , Asafa, T. B. , Sadiku, E. R. , Diouf, S. , Shongwe, M. B. , Olubambi, P. A. , Oladosu, K. O. , Ogbemudia, A. , Babalola, M. M. , Ajala, M. T.
- Date: 2020
- Subjects: Composites , Graphie-aluminium , Eggshells
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/464591 , uj:41511 , Citation: Durowoju, M.O. et al. 2020. Improving mechanical and thermal properties of graphite–aluminium composite using Si, SiC and eggshell particles. , DOI: 10.1177/0021998319892058
- Description: Abstract: Please refer to full text to view abstract.
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Influence of anionic surfactants on the stability of multi-walled carbon nanotubes-based nanofluid
- Authors: Borode, A. O. , Ahmed, N. A. , Olubambi, P. A.
- Date: 2021
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/480111 , uj:43450 , Citation: A.O. Borode et al 2021 IOP Conf. Ser.: Mater. Sci. Eng. 1107 012196 , DOI: 10.1088/1757-899X/1107/1/012196
- Description: Abstract: Please refer to full text to view abstract.
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Influence of spark plasma sintering temperature on the densification and micro-hardness behaviour of Ni-Cr-Al alloy
- Authors: Babalola, B. J. , Shongwe, M. B. , Jeje, O. O. , Rominiyi, A. L. , Ayodele, O. O. , Olubambi, P. A.
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/405772 , uj:34088 , Citation: Babalola, B.J. et al. 2019 : Influence of spark plasma sintering temperature on the densification and micro-hardness behaviour of Ni-Cr-Al alloy. IOP Conf. Series: Materials Science and Engineering 655 (2019) 012032. DOI:10.1088/1757-899X/655/1/012032.
- Description: Abstract : Sintering temperature is essential towards attaining desired densification and formation of phases which in turn influences the microstructure and properties of a material. In this study, the densification and microhardness behaviour of Ni-Cr-Al alloy prepared by spark plasma sintering (SPS) at different sintering temperatures were investigated. After sintering operation, the density, hardness, phase analysis, and microstructural evolution were investigated using the Archimede’s principle, hardness tester, X-ray diffraction (XRD), and scanning electron microscopy (SEM) respectively. The nickel based alloy was sintered at temperatures of 600, 750, 950 and 1100 ºC. The results indicated that the densification, microstructure, and hardness values were influenced by changes in the sintering temperature. The relative density increased from 73.89 % at 600 ºC to 99.89 % at 1100 ºC, while the hardness value was enhanced from 131.9 ± 2.8 HV to 404 ± 1.2 HV respectively.
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Microstructural and mechanical properties of spark plasma sintering of Ni2 Cr11Al powders synthesized by mechanical alloying for thermal barrier coating
- Authors: Omoniyi, F. I. S. , Olubambi, P. A. , Sadiku, R. E.
- Date: 2018
- Subjects: Mechanical alloying , Mechanical properties , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/282329 , uj:30407 , Citation: Omoniyi, F.I.S., Olubambi, P.A. & Sadiku, R.E. 2018. Microstructural and mechanical properties of spark plasma sintering of Ni2 Cr11Al powders synthesized by mechanical alloying for thermal barrier coating.
- Description: Abstract: Thermal barrier coatings (TBCs) systems are used to protect hot sections of industrial gas turbine blades against high temperature corrosion and oxidation. Currently, MCrAlY powders up to 100 μm in diameter are used in the production of thermal barrier coatings by industrial gas turbine component manufacturers. It has been found that nanocrystalline MCrAlY layer provide better oxidation behaviour than currently used microstructure MCrAlY layer at elevated temperature. In the present study, nanocrystalline NI22Cr11Al composites was synthesized using high energy planetary ball milling for different periods of time, and the dense NI22Cr11Al alloy was fabricated by using spark plasma sintering process at different temperatures ranging from 1000°C to 1200°C. The resultant powder particles, bulk and dense samples were characterised using scanning electron microscope (SEM), X-ray diffraction analysis (XRD) and Micro Vickers hardness test. The results indicated that mechanical milling process produce morphology changes, particle size increase, crystallite size decrease down to nanometric level (40 nm) and formation of Nano dispersions in the process.
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Spark plasma sintered Ti6Al4V-ZrO2 bio-composites: optimization of ball milling and turbula mixing of powders and their subsequent sintering parameters
- Authors: Moshokoa, N. A. , Mukhudwana, T. V. , Raganya, L. M. , Lekgoathi, J. I. , Obadele, B. A. , Olubambi, P. A.
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/279912 , uj:30069 , Citation: Moshokoa, N.A. et al. 2018. Spark plasma sintered Ti6Al4V-ZrO2 bio-composites: optimization of ball milling and turbula mixing of powders and their subsequent sintering parameters. IOP Conf. Series: Materials Science and Engineering 430 (2018) 012035 doi:10.1088/1757-899X/430/1/012035
- Description: Abstract: The use of Ti6Al4V as a biomaterial has been limited due to the dissociation of V and Al ions into the surrounding environment which can cause inflammations, cell damage and toxicity. To prohibit these undesirable challenges, the addition of ZrO2 into Ti6Al4V was proposed because ZrO2 is biocompatible, it has good wear and corrosion resistant properties, it has low affinity to bacterial colonization and it has high fracture toughness.The aim of this work is to determine the optimum powder synthesising parameters by Tubular mixer and ball mill for fabrication of sintered composites . Powder mixtures were prepared by 49 rpm,72 rpm and 74rpm for 2, 4 and 8 hours followed by spark plasma sintering at 1100 oC at heating rate of 100 oC/min for 10 min and pressure of 50 MPa.from the results obtained it was discovered that Tubular mixing of 90 Vol% Ti6Al4V and 10 Vol% ZrO2 at 72 rpm and ball milling of 90 Vol% Ti6Al4V and 10 Vol% ZrO2 at 74rpm speed have proved to produce homogeneous admixed powders, which can further produce fully dense SPS compacts with higher microhardness values.
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Structural integrity and dispersion characteristics of carbon nanotubes in titanium-based alloy
- Authors: Okoro, A. M. , Machaka, R. , Lephuthing, S. S. , Awotunde, M. , Olubambi, P. A.
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/279905 , uj:30068 , Citation: Okoro, A.M. et al. 2018. Structural integrity and dispersion characteristics of carbon nanotubes in titanium-based alloy. IOP Conf. Series: Materials Science and Engineering 430 (2018) 012004 doi:10.1088/1757-899X/430/1/012004
- Description: Abstract: Over the years, carbon nanotubes have attracted much attention in engineering materials research due to their outstanding and superlative properties. Owing to the demands for lightweight materials with excellent mechanical and thermal properties for diverse industrial applications encouraged the incorporation of carbon nanotubes into titanium alloys. However, there are various challenges associated with the incorporation of carbon nanotubes into titanium alloys which includes; uniform dispersion and retaining the structural integrity of carbon nanotubes after dispersion. Past works have emphasized the importance of homogeneous dispersion with less structural damage to the carbon nanotubes in the various metal matrix. Therefore, this research focused on dispersion of 0.5 wt. % multiwalled carbon nanotubes in Ti6Al4V using low energy ball milling and evaluating the dispersion characteristics and structural integrity of MWCNTs in Ti6Al4V after dispersion. Various characterization techniques such as high-resolution transmission electron microscopy, scanning electron microscopy, X-Ray diffraction and Raman spectroscopy were adopted to ascertain the microstructural evolution, morphology, interfacial reaction and structural integrity of the carbon nanotubes in the Ti6Al4V powders before and after dispersion. The results indicated homogeneous dispersion of carbon nanotubes with less structural damages which are confirmed from the (ID/IG) ratio of the Raman spectra and the TEM images.
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The role of graphite addition on spark plasma sintered titanium nitride
- Authors: Akinribide, O. J. , Obadele, B. A. , Ayeleru, O. O. , Akinwamide, S. O. , Nomoto, K. , Eizadjou, M. , Ringer, S. P. , Olubambi, P. A.
- Date: 2020
- Subjects: TiN , Graphite , Spark plasma sintering
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/451622 , uj:39803 , Citation: Akinribide, O.J. et al. 2020. The role of graphite addition on spark plasma sintered titanium nitride. , DOI: https://doi.org/10.1016/j.jmrt.2020.03.040
- Description: Abstract: tComposites of titanium nitride reinforced with graphite were synthesized using sparkplasma sintering at 2000◦C. The effects of graphite addition on the microstructure, relativedensity, and mechanical properties of TiN ceramics matrix were examined. The investiga-tion was performed on TiN powder with varying graphite content (1–5 wt.%) for 8 h using anenergy ball milling equipment. Results show that TiN without and with graphite (TiN + 1 wt.%graphite) sintered at 2000◦C recorded sintered relative density of 96.7% and 97% respec-tively. Additionally, TiN with 3 wt.% graphite had a relative density of 98%. However, theshrinkage of TiN + 3 wt.% graphite was observed to be the lowest compared to other com-posites at the same sintering conditions. Microstructural analysis indicates that the grainof titanium nitride in the composite was very fine and continuous. Subsequently, a bimodalparticle sizes were observed when 5 wt.% graphite was dispersed in TiN. The highest Vickersmicrohardness of 23.5 GPa and fracture toughness of 6.5 MPa m1/2were achieved with com-posites reinforced with 3 wt.% graphite at milling period of 8 h. The combination of TEM/EDSand HRTEM/FFT show a single pattern of diffraction and consistency in interplanar distanceobtained from X-ray diffractometry of the milled sample. There is a clear coherence interfacebetween the phases.
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