The influence of scanning speed and number of scans on the properties of laser formed steel
- Sanusi, Kazeem Oladele, Akinlabi, Stephen, Akinlabi, Esther Titilayo
- Authors: Sanusi, Kazeem Oladele , Akinlabi, Stephen , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Laser beam forming , Scanning speed , Laser power , Mechanical , Microstructure , Micro hardness , Number of scan
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93743 , uj:20385 , Citation: Sanusi, K.O., Akinlabi, S. & Akinlabi, E.T. 2016. The influence of scanning speed and number of scans on the properties of laser formed steel.
- Description: Abstract: Laser Beam Forming (LBF) process is an emerging and new forming method that generally requires brute force to forge the steel into the desired shape instead of using conventional methods. This study investigates the changes that occur in low carbon steel through the laser beam forming process. The parameters under investigation include variable scanning speed and number of scans at fixed laser intensity. The effect of these laser parameters on the chemical composition and properties of low carbon steel is assessed through characterisation of both the as received and LBF formed specimens. Characterizations of the laser formed steels were studied using microstructural analysis and micro hardness profiling. The results show that there is a significant increase in the mechanical properties of the LBF formed materials. Scanning power and the number of scans have a noticeable effect on the curvature achieved in the formed samples.The results obtained will contribute towards the further optimization of laser forming methods for steel for the optimization of the properties of steel using Laser Beam Forming process.
- Full Text:
- Authors: Sanusi, Kazeem Oladele , Akinlabi, Stephen , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Laser beam forming , Scanning speed , Laser power , Mechanical , Microstructure , Micro hardness , Number of scan
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93743 , uj:20385 , Citation: Sanusi, K.O., Akinlabi, S. & Akinlabi, E.T. 2016. The influence of scanning speed and number of scans on the properties of laser formed steel.
- Description: Abstract: Laser Beam Forming (LBF) process is an emerging and new forming method that generally requires brute force to forge the steel into the desired shape instead of using conventional methods. This study investigates the changes that occur in low carbon steel through the laser beam forming process. The parameters under investigation include variable scanning speed and number of scans at fixed laser intensity. The effect of these laser parameters on the chemical composition and properties of low carbon steel is assessed through characterisation of both the as received and LBF formed specimens. Characterizations of the laser formed steels were studied using microstructural analysis and micro hardness profiling. The results show that there is a significant increase in the mechanical properties of the LBF formed materials. Scanning power and the number of scans have a noticeable effect on the curvature achieved in the formed samples.The results obtained will contribute towards the further optimization of laser forming methods for steel for the optimization of the properties of steel using Laser Beam Forming process.
- Full Text:
Property evolution of thermo-mechanically treated reinforcement bar
- Musonda, V., Akinlabi, Esther Titilayo
- Authors: Musonda, V. , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: Property evolution , Microstructure , Reinforcement bars
- Language: English
- Type: Conference proceeding
- Identifier: http://hdl.handle.net/10210/291125 , uj:31608 , Citation: Musonda, V. & Akinlabi, E.T. 2018. Property evolution of thermo-mechanically treated reinforcement bar.
- Description: Abstract: Property evolution of microstructure of reinforcement bar (rebar) depends on how well the steel is treated during and after the Thermomechanical Treatment (TMT) box. Rebars are hot rolled - from low carbon steel through Tempcore technology. In order to achieve optimal properties, typical evolving mechanical properties of the rebar such as ultimate tensile strength (UTS), yield stress (YS) and the percentage elongation (%El) were conducted. This is necessary to control the tempering and cooling process. In this study, a simulation of the cooling rebar was investigated using finite element modelling (FEM). The material used for the model and production of the rebar was equivalent to AISI 1016 carbon steel and was produced from scrap supplemented with Direct Reduced Iron (DRI). The raw materials were melted in an Electric Arc Furnace (EAF) prior to hot rolling through a billet caster. The rod mill tensile test report showed that UTS and YS values ranged between 482 MPa for the YS and 650 MPa for UTS on an average. The average percentage elongation was found to be 23 % well above the 14 % threshold according to the standard. The pearlite-ferrite microstructure and the martensite developed is in agreement with the standard microstructure found in the literature.
- Full Text:
- Authors: Musonda, V. , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: Property evolution , Microstructure , Reinforcement bars
- Language: English
- Type: Conference proceeding
- Identifier: http://hdl.handle.net/10210/291125 , uj:31608 , Citation: Musonda, V. & Akinlabi, E.T. 2018. Property evolution of thermo-mechanically treated reinforcement bar.
- Description: Abstract: Property evolution of microstructure of reinforcement bar (rebar) depends on how well the steel is treated during and after the Thermomechanical Treatment (TMT) box. Rebars are hot rolled - from low carbon steel through Tempcore technology. In order to achieve optimal properties, typical evolving mechanical properties of the rebar such as ultimate tensile strength (UTS), yield stress (YS) and the percentage elongation (%El) were conducted. This is necessary to control the tempering and cooling process. In this study, a simulation of the cooling rebar was investigated using finite element modelling (FEM). The material used for the model and production of the rebar was equivalent to AISI 1016 carbon steel and was produced from scrap supplemented with Direct Reduced Iron (DRI). The raw materials were melted in an Electric Arc Furnace (EAF) prior to hot rolling through a billet caster. The rod mill tensile test report showed that UTS and YS values ranged between 482 MPa for the YS and 650 MPa for UTS on an average. The average percentage elongation was found to be 23 % well above the 14 % threshold according to the standard. The pearlite-ferrite microstructure and the martensite developed is in agreement with the standard microstructure found in the literature.
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Production and characterization of titanium carbide particulate reinforced AA6061 aluminum alloy composites using stir casting
- Moses, J. Jebeen, Dinaharan, I., Sekhar, S. Joseph
- Authors: Moses, J. Jebeen , Dinaharan, I. , Sekhar, S. Joseph
- Date: 2016
- Subjects: Metal matrix composites , Stir casting , Microstructure , Mechanical properties
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93822 , uj:20395 , Citation: Moses, J.J., Dinaharan, I. & Sekhar, S.J. 2016. Production and characterization of titanium carbide particulate reinforced AA6061 aluminum alloy composites using stir casting.
- Description: Abstract: Stir casting is an economical method to produce aluminum matrix composites. In the present work, composites of aluminum alloy AA6061 reinforced with various amounts (0, 5, 10 and 15wt. %) of TiC particles were prepared by stir casting technique. X-ray diffraction patterns of the prepared composites clearly revealed the incorporation of TiC particles without the presence of any other compounds. The microstructures of the composites were studied using optical and scanning electron microscopy. It was observed that the TiC particles distributed all over the composite and properly bonded to the matrix alloy. Local clusters of TiC particle were also seen in a few places. The result shows that the reinforcement of TiC particles enhances the microhardness, ultimate tensile strength and wear resistance of the composite. The details of fracture morphology, worn surface and wear debris are also presented in this paper.
- Full Text:
- Authors: Moses, J. Jebeen , Dinaharan, I. , Sekhar, S. Joseph
- Date: 2016
- Subjects: Metal matrix composites , Stir casting , Microstructure , Mechanical properties
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93822 , uj:20395 , Citation: Moses, J.J., Dinaharan, I. & Sekhar, S.J. 2016. Production and characterization of titanium carbide particulate reinforced AA6061 aluminum alloy composites using stir casting.
- Description: Abstract: Stir casting is an economical method to produce aluminum matrix composites. In the present work, composites of aluminum alloy AA6061 reinforced with various amounts (0, 5, 10 and 15wt. %) of TiC particles were prepared by stir casting technique. X-ray diffraction patterns of the prepared composites clearly revealed the incorporation of TiC particles without the presence of any other compounds. The microstructures of the composites were studied using optical and scanning electron microscopy. It was observed that the TiC particles distributed all over the composite and properly bonded to the matrix alloy. Local clusters of TiC particle were also seen in a few places. The result shows that the reinforcement of TiC particles enhances the microhardness, ultimate tensile strength and wear resistance of the composite. The details of fracture morphology, worn surface and wear debris are also presented in this paper.
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Microstructure evolution and mechanical characterization of friction stir welded titanium alloy Ti–6Al–4V using lanthanated tungsten tool
- Mashinini, P. M., Dinaharan, I., Selvama, J. David Raja, Hattingh, D. G.
- Authors: Mashinini, P. M. , Dinaharan, I. , Selvama, J. David Raja , Hattingh, D. G.
- Date: 2018
- Subjects: Titanium alloy , Friction stir welding , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273276 , uj:29110 , Citation: Mashinini, P.M. et al. 2018. Microstructure evolution and mechanical characterization of friction stir welded titanium alloy Ti–6Al–4V using lanthanated tungsten tool.
- Description: Abstract: Friction stir welding (FSW) exhibits significant advantages to join titanium and its alloys compared to other welding methods. FSW of 3 mm thick titanium alloy Ti–6Al–4V sheets was carried out using a lanthanated tungsten alloy tool. The traverse speed was varied from 40 mm/min to 200 mm/min in steps of 80 mm/min by keeping other parameters constant. The microstructure evolution was observed using conventional and advanced characterization techniques. The micrographs revealed a fully developed lamellar structure at 40 mm/min and a recrystallized structure in rest of the joints. An increase in β phase was observed at HAZ while TMAZ showed a distorted structure. The average grain size was observed to reduce with an increase in traverse speed. No tool wear debris was observed in the stir zone while a worm hole defect was noticed at 200 mm/min. Ti–6Al–4V hardened...
- Full Text:
- Authors: Mashinini, P. M. , Dinaharan, I. , Selvama, J. David Raja , Hattingh, D. G.
- Date: 2018
- Subjects: Titanium alloy , Friction stir welding , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273276 , uj:29110 , Citation: Mashinini, P.M. et al. 2018. Microstructure evolution and mechanical characterization of friction stir welded titanium alloy Ti–6Al–4V using lanthanated tungsten tool.
- Description: Abstract: Friction stir welding (FSW) exhibits significant advantages to join titanium and its alloys compared to other welding methods. FSW of 3 mm thick titanium alloy Ti–6Al–4V sheets was carried out using a lanthanated tungsten alloy tool. The traverse speed was varied from 40 mm/min to 200 mm/min in steps of 80 mm/min by keeping other parameters constant. The microstructure evolution was observed using conventional and advanced characterization techniques. The micrographs revealed a fully developed lamellar structure at 40 mm/min and a recrystallized structure in rest of the joints. An increase in β phase was observed at HAZ while TMAZ showed a distorted structure. The average grain size was observed to reduce with an increase in traverse speed. No tool wear debris was observed in the stir zone while a worm hole defect was noticed at 200 mm/min. Ti–6Al–4V hardened...
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Microstructure and microhardness of 17-4 ph stainless steel made by laser metal deposition
- Bayode, A., Akinlabi, Esther Titilayo, Pityana, S.
- Authors: Bayode, A. , Akinlabi, Esther Titilayo , Pityana, S.
- Date: 2016
- Subjects: Additive manufacturing , Laser metal deposition , Microstructure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214385 , uj:21275 , Citation: Bayode, A., Akinlabi, E & Pityana, S. 2016. Microstructure and microhardness of 17-4 ph stainless steel made by laser metal deposition.
- Description: Abstract: Laser metal deposition (LMD) is an additive manufacturing process. Unlike conventional manufacturing process which is subtractive, LMD produces part layer by layer from the ground up and has been used to fabricate fully dense components using a variety of metallic powders. This paper investigates the evolving properties of laser deposited 17- 4PH stainless steel. The microstructure was martensitic with a dendritic structure. The average microhardness of the samples was found to be less than their wrought counterpart.
- Full Text:
- Authors: Bayode, A. , Akinlabi, Esther Titilayo , Pityana, S.
- Date: 2016
- Subjects: Additive manufacturing , Laser metal deposition , Microstructure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214385 , uj:21275 , Citation: Bayode, A., Akinlabi, E & Pityana, S. 2016. Microstructure and microhardness of 17-4 ph stainless steel made by laser metal deposition.
- Description: Abstract: Laser metal deposition (LMD) is an additive manufacturing process. Unlike conventional manufacturing process which is subtractive, LMD produces part layer by layer from the ground up and has been used to fabricate fully dense components using a variety of metallic powders. This paper investigates the evolving properties of laser deposited 17- 4PH stainless steel. The microstructure was martensitic with a dendritic structure. The average microhardness of the samples was found to be less than their wrought counterpart.
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Microstructure and mechanical characterization of in situ synthesized AA6061/(TiB2+Al2O3) hybrid aluminum matrix composites
- Selvam, J. David Raja, Dinaharan, I., Vibin Philip, S., Mashinini, P. M.
- Authors: Selvam, J. David Raja , Dinaharan, I. , Vibin Philip, S. , Mashinini, P. M.
- Date: 2018
- Subjects: Aluminum matrix composites , Casting , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273033 , uj:29080 , Citation: Selvam, J.D.R., Dinaharan, I., Vibin Philip, S. & Mashinini, P. M. 2018. Microstructure and mechanical characterization of in situ synthesized AA6061/(TiB2+Al2O3) hybrid aluminum matrix composites.
- Description: Abstract: TiB2 and Al2O3 particulates reinforced AA6061 aluminum matrix composites (AMCs) were synthesized by in-situ reaction of titanium (Ti) and boric acid (H3BO3) powders with molten aluminum. AMCs were fabricated using an electric stir casting furnace under a controlled environment. Heat flow curves of differential thermal analysis (DTA) showed that the synthesis temperature for the formation of TiB2 and Al2O3 using Al-Ti-H3BO3 reaction system was 950°C. The in-situ synthesized composites were characterized using XRD, FESEM, TEM and EBSD. XRD results revealed the formation of TiB2 and Al2O3 particulates in the composite. FESEM micrographs revealed a homogenous distribution of both the particulates with good interfacial bonding. EBSD maps showed that the in-situ formed TiB2 and Al2O3 particulates refined the grains of the aluminum matrix from 103 μm at 0 wt.% to 14 μm at 15 wt.%. Al2O3 particles exhibited spherical shape while TiB2 particles displayed hexagonal and cubic shapes. The formation of ultrafine and nano scale thermodynamically stable TiB2 and Al2O3 particles enhanced the microhardness and the tensile strength of the 2 AMCs. The microhardness and the tensile strength were respectively 122 HV and 287 MPa at 15 wt.%.
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- Authors: Selvam, J. David Raja , Dinaharan, I. , Vibin Philip, S. , Mashinini, P. M.
- Date: 2018
- Subjects: Aluminum matrix composites , Casting , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273033 , uj:29080 , Citation: Selvam, J.D.R., Dinaharan, I., Vibin Philip, S. & Mashinini, P. M. 2018. Microstructure and mechanical characterization of in situ synthesized AA6061/(TiB2+Al2O3) hybrid aluminum matrix composites.
- Description: Abstract: TiB2 and Al2O3 particulates reinforced AA6061 aluminum matrix composites (AMCs) were synthesized by in-situ reaction of titanium (Ti) and boric acid (H3BO3) powders with molten aluminum. AMCs were fabricated using an electric stir casting furnace under a controlled environment. Heat flow curves of differential thermal analysis (DTA) showed that the synthesis temperature for the formation of TiB2 and Al2O3 using Al-Ti-H3BO3 reaction system was 950°C. The in-situ synthesized composites were characterized using XRD, FESEM, TEM and EBSD. XRD results revealed the formation of TiB2 and Al2O3 particulates in the composite. FESEM micrographs revealed a homogenous distribution of both the particulates with good interfacial bonding. EBSD maps showed that the in-situ formed TiB2 and Al2O3 particulates refined the grains of the aluminum matrix from 103 μm at 0 wt.% to 14 μm at 15 wt.%. Al2O3 particles exhibited spherical shape while TiB2 particles displayed hexagonal and cubic shapes. The formation of ultrafine and nano scale thermodynamically stable TiB2 and Al2O3 particles enhanced the microhardness and the tensile strength of the 2 AMCs. The microhardness and the tensile strength were respectively 122 HV and 287 MPa at 15 wt.%.
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Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten
- Adeyemi, A.A., Akinlabi, Esther Titilayo, Mahamood, R.M.
- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M.
- Date: 2018
- Subjects: Laser Metal Deposition , Laser Power , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/290972 , uj:31595 , Citation: Adeyemi, A.A., Akinlabi, E.T. & Mahamood, R.M. 2018. Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten.
- Description: Abstract: This study investigates the influence of quantity of tungsten powder on the microstructural evolution of 17-4 PH stainless steel-tungsten composite produced using laser metal deposition process. The 17-4 PH stainless steel and tungsten powders were deposited on 316 stainless steel substrate at laser power of 2600 W. The tungsten powder flow rate was varied between 0.5 rpm and 2.0 rpm while 17-4 PH stainless steel powder flow rate, the scanning speed, the gas flow rate and the laser spot size were fixed at 2.0 rpm, 0.5 m/s, 2.5 l/min and 2.0 mm respectively. Five (5) multiple track of 17-4 PH stainless steel and tungsten powder were deposited on 316 stainless steel of thickness 10 mm from different hopper at 50% overlapping percentage to produce 17-4 PH SS-W composite. During the microstructural study, it was observed that tungsten carbide has been precipitated in-situ and evenly dispersed in the 17-4 PH SS-W composite produced. SEM and EDS analysis also revealed the presence of BCC alpha (α) ferrite and FCC gamma (δ) ferrite with the presence of sigma (σ) phase precipitates.
- Full Text:
- Authors: Adeyemi, A.A. , Akinlabi, Esther Titilayo , Mahamood, R.M.
- Date: 2018
- Subjects: Laser Metal Deposition , Laser Power , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/290972 , uj:31595 , Citation: Adeyemi, A.A., Akinlabi, E.T. & Mahamood, R.M. 2018. Microstructural evolution of laser metal deposited 17-4 PH SS-tungsten composite with varying volume percent tungsten.
- Description: Abstract: This study investigates the influence of quantity of tungsten powder on the microstructural evolution of 17-4 PH stainless steel-tungsten composite produced using laser metal deposition process. The 17-4 PH stainless steel and tungsten powders were deposited on 316 stainless steel substrate at laser power of 2600 W. The tungsten powder flow rate was varied between 0.5 rpm and 2.0 rpm while 17-4 PH stainless steel powder flow rate, the scanning speed, the gas flow rate and the laser spot size were fixed at 2.0 rpm, 0.5 m/s, 2.5 l/min and 2.0 mm respectively. Five (5) multiple track of 17-4 PH stainless steel and tungsten powder were deposited on 316 stainless steel of thickness 10 mm from different hopper at 50% overlapping percentage to produce 17-4 PH SS-W composite. During the microstructural study, it was observed that tungsten carbide has been precipitated in-situ and evenly dispersed in the 17-4 PH SS-W composite produced. SEM and EDS analysis also revealed the presence of BCC alpha (α) ferrite and FCC gamma (δ) ferrite with the presence of sigma (σ) phase precipitates.
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Microstructural characterization and hardness properties of magnesium alloy processed by high pressure torsion
- Sanusi, Kazeem O., Madushele, Nkosinathi, Akinlabi, Esther Titilayo
- Authors: Sanusi, Kazeem O. , Madushele, Nkosinathi , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: High pressure torsion , Pure magnesium , Microstructure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/260622 , uj:27448 , Citation: Sanusi, K.O., Madushele, N. & Akinlabi, E.T. 2018. Microstructural characterization and hardness properties of magnesium alloy processed by high pressure torsion.
- Description: Abstract: Magnesium and magnesium alloys are the lightest of all metal used for structural construction. This property of magnesium made it to be the most used material in the automobile manufacturing industries and in aerospace as well as in other industries. This research is based on the process improvement of pure commensally magnesium alloy (Mg 99.94%) using high pressure torsion (HPT) process. The investigation was based on the measurement of hardness properties and microstructural characterization of magnesium alloy processed by high pressure torsion (HPT).
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- Authors: Sanusi, Kazeem O. , Madushele, Nkosinathi , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: High pressure torsion , Pure magnesium , Microstructure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/260622 , uj:27448 , Citation: Sanusi, K.O., Madushele, N. & Akinlabi, E.T. 2018. Microstructural characterization and hardness properties of magnesium alloy processed by high pressure torsion.
- Description: Abstract: Magnesium and magnesium alloys are the lightest of all metal used for structural construction. This property of magnesium made it to be the most used material in the automobile manufacturing industries and in aerospace as well as in other industries. This research is based on the process improvement of pure commensally magnesium alloy (Mg 99.94%) using high pressure torsion (HPT) process. The investigation was based on the measurement of hardness properties and microstructural characterization of magnesium alloy processed by high pressure torsion (HPT).
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Microstructural and mechanical properties of spark plasma sintering of Ni2 Cr11Al powders synthesized by mechanical alloying for thermal barrier coating
- Omoniyi, F. I. S., Olubambi, P. A., Sadiku, R. E.
- 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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- 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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Microstructural and electrochemical studies of spark plasma sintered multiwall carbon nanotubes reinforced TiO2eMnO2 based composite
- Lephuthing, Senzeni Sipho, Okoro, Avwerosuoghene Moses, Ige, Oladeji Oluremi, Olunambi, Peter Apata
- Authors: Lephuthing, Senzeni Sipho , Okoro, Avwerosuoghene Moses , Ige, Oladeji Oluremi , Olunambi, Peter Apata
- Date: 2020
- Subjects: Microstructure , Spark plasma sintering , Electrochemical study
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480894 , uj:43549 , Citation: Lephuting, S.S., Okoro, A.M., Ige, O.O., Olunambi, P.A. 2020. Microstructural and electrochemical studies of spark plasma sintered multiwall carbon nanotubes reinforced TiO2eMnO2 based composite. DOI:
- Description: Abstract: An electrochemical study was conducted to investigate the suitability of TiO2, TiO2- MWCNTs and (5,10 and 15 wt.%) of MnO2 in TiO2-MWCNTs composites as dimensional stable electrodes which were developed via conventional powder processing and spark plasma sintering. The following electrochemical tests were carried out including open circuit potential, galvanostatic chronoamperometry and cyclic voltammetry measurements. The results showed that an increase on MnO2 content in the composites did not only lower the potentials but enhanced the stability of the composites. The degradation which translates to corrosion susceptibility was favorable on composite samples with lower MnO2 content. Also, the presence of MWCNTs in the composites improved the electrocatalytic capacity of the material. Furthermore, the anodic layers formed on the composites during polarization was analyzed using SEM, XRD and cyclic voltammetry. The results showed that the formation of anodic layer during 24 h of polarization increased with the addition of MnO2 content and 15 MnO2eTiO2-MWCNT composite grade showed minimal pores after polarization which translates to higher protection.
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- Authors: Lephuthing, Senzeni Sipho , Okoro, Avwerosuoghene Moses , Ige, Oladeji Oluremi , Olunambi, Peter Apata
- Date: 2020
- Subjects: Microstructure , Spark plasma sintering , Electrochemical study
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480894 , uj:43549 , Citation: Lephuting, S.S., Okoro, A.M., Ige, O.O., Olunambi, P.A. 2020. Microstructural and electrochemical studies of spark plasma sintered multiwall carbon nanotubes reinforced TiO2eMnO2 based composite. DOI:
- Description: Abstract: An electrochemical study was conducted to investigate the suitability of TiO2, TiO2- MWCNTs and (5,10 and 15 wt.%) of MnO2 in TiO2-MWCNTs composites as dimensional stable electrodes which were developed via conventional powder processing and spark plasma sintering. The following electrochemical tests were carried out including open circuit potential, galvanostatic chronoamperometry and cyclic voltammetry measurements. The results showed that an increase on MnO2 content in the composites did not only lower the potentials but enhanced the stability of the composites. The degradation which translates to corrosion susceptibility was favorable on composite samples with lower MnO2 content. Also, the presence of MWCNTs in the composites improved the electrocatalytic capacity of the material. Furthermore, the anodic layers formed on the composites during polarization was analyzed using SEM, XRD and cyclic voltammetry. The results showed that the formation of anodic layer during 24 h of polarization increased with the addition of MnO2 content and 15 MnO2eTiO2-MWCNT composite grade showed minimal pores after polarization which translates to higher protection.
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Laser surface modification of Ti6Al4V-Cu for improved microhardness and wear resistance properties
- Erinosho, Mutiu F, Akinlabi, Esther Titilayo, Pityana, Sisa, Owolabi, Gbadebo
- Authors: Erinosho, Mutiu F , Akinlabi, Esther Titilayo , Pityana, Sisa , Owolabi, Gbadebo
- Date: 2017
- Subjects: Dry sliding wear , Laser metal deposition , Microstructure
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/241797 , uj:24925 , Citation: Erinosho, M.F. et al. 2017. Laser surface modification of Ti6Al4V-Cu for improved microhardness and wear resistance properties.
- Description: Abstract: The light weight of Ti6Al4V as a titanium alloy is been amongst the properties that have been tailed for the aerospace and other industrial applications. To modify the properties of this alloy, Cu has been added to host an antimicrobial effect in the revised alloy for marine application. The LMD process on the Ti6Al4V alloy and Cu was been investigated for surface modification in order to combat the problem of biofouling in the marine industry. The investigations focused on the microstructural observations, micro-hardness measurements and dry sliding wear in the presence of 3 and 5 weight percents of Cu. The microstructure results showed that Widmanstätten microstructures were formed in all the samples and lose their robustness towards the fusion zone as a result of the transition of heat sink towards the substrate. The microhardness values of Ti6Al4V-3Cu and Ti6Al4V-5Cu alloys were greatly improved to 547±16 VHN0.5 and 519±54 VHN0.5 respectively. In addition, the behaviour of wear loss on the surface of the Ti6Al4V-Cu alloys exhibited great improvement as compared with the parent...
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- Authors: Erinosho, Mutiu F , Akinlabi, Esther Titilayo , Pityana, Sisa , Owolabi, Gbadebo
- Date: 2017
- Subjects: Dry sliding wear , Laser metal deposition , Microstructure
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/241797 , uj:24925 , Citation: Erinosho, M.F. et al. 2017. Laser surface modification of Ti6Al4V-Cu for improved microhardness and wear resistance properties.
- Description: Abstract: The light weight of Ti6Al4V as a titanium alloy is been amongst the properties that have been tailed for the aerospace and other industrial applications. To modify the properties of this alloy, Cu has been added to host an antimicrobial effect in the revised alloy for marine application. The LMD process on the Ti6Al4V alloy and Cu was been investigated for surface modification in order to combat the problem of biofouling in the marine industry. The investigations focused on the microstructural observations, micro-hardness measurements and dry sliding wear in the presence of 3 and 5 weight percents of Cu. The microstructure results showed that Widmanstätten microstructures were formed in all the samples and lose their robustness towards the fusion zone as a result of the transition of heat sink towards the substrate. The microhardness values of Ti6Al4V-3Cu and Ti6Al4V-5Cu alloys were greatly improved to 547±16 VHN0.5 and 519±54 VHN0.5 respectively. In addition, the behaviour of wear loss on the surface of the Ti6Al4V-Cu alloys exhibited great improvement as compared with the parent...
- Full Text:
Laser metal deposition of Ti6Al4V : a study on the effect of laser power on microstructure and microhardness
- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo, Shukla, Mukul, Pityana, Sisa
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2013
- Subjects: Laser metal deposition process , Laser power , Ti6Al4V , Macroscopic banding , Microhardness , Microstructure
- Type: Article
- Identifier: uj:4896 , http://hdl.handle.net/10210/12610
- Description: The effect of laser power on the resulting microstructure and microhardness of laser metal deposited Ti6Al4V powder on Ti6Al4V substrate has been investigated. The tracks were deposited using 99.6 % pure Ti6Al4V powder of particle size ranging between 150 - 200 μm on 99.6% Ti6Al4V substrate. The laser power was varied between 0.8 - 3.0 kW while the scanning speed, powder flow rate and the gas flow rate were kept at the values of 0.005 m/sec, 1.44 g/min and 4 l /min respectively. The microstructure and the microhardness were studied using the optical microscope and the Vickers hardness tester respectively. Layer band or macroscopic banding was observed in all the samples which is phenomenon as it was only reported in the literature for multi-layer deposits. The literature attributed re-melting of the previous layers by the succeeding layers as being responsible for their formation. This study has revealed that this band could be as a result of shrinkage happening in the fusion zone as a result of the interaction of the deposited powder and the melt pool created by the substrate material. This study also reveals the relationship between the microstructure, the average microhardness and the laser power which are comprehensively discussed. The higher the laser power, the lower the density of columnar prior beta grain structure. Also the average microhardness increases as the laser power increases.
- Full Text:
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2013
- Subjects: Laser metal deposition process , Laser power , Ti6Al4V , Macroscopic banding , Microhardness , Microstructure
- Type: Article
- Identifier: uj:4896 , http://hdl.handle.net/10210/12610
- Description: The effect of laser power on the resulting microstructure and microhardness of laser metal deposited Ti6Al4V powder on Ti6Al4V substrate has been investigated. The tracks were deposited using 99.6 % pure Ti6Al4V powder of particle size ranging between 150 - 200 μm on 99.6% Ti6Al4V substrate. The laser power was varied between 0.8 - 3.0 kW while the scanning speed, powder flow rate and the gas flow rate were kept at the values of 0.005 m/sec, 1.44 g/min and 4 l /min respectively. The microstructure and the microhardness were studied using the optical microscope and the Vickers hardness tester respectively. Layer band or macroscopic banding was observed in all the samples which is phenomenon as it was only reported in the literature for multi-layer deposits. The literature attributed re-melting of the previous layers by the succeeding layers as being responsible for their formation. This study has revealed that this band could be as a result of shrinkage happening in the fusion zone as a result of the interaction of the deposited powder and the melt pool created by the substrate material. This study also reveals the relationship between the microstructure, the average microhardness and the laser power which are comprehensively discussed. The higher the laser power, the lower the density of columnar prior beta grain structure. Also the average microhardness increases as the laser power increases.
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Influence of tool rotational speed on microstructure and joint strength of friction stir spot welded pure copper
- Dinaharan, I., Akinlabi, Esther Titilayo
- Authors: Dinaharan, I. , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Copper , Friction stir spot welding , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/214059 , uj:21231 , Citation: Dinaharan, I & Akinlabi, E.T. 2016. Influence of tool rotational speed on microstructure and joint strength of friction stir spot welded pure copper.
- Description: Abstract: Copper is very difficult to be spot welded by conventional fusion welding techniques due to higher thermal diffusivity. Friction stir spot welding (FSSW) is a novel solid state welding process which is suitable and competent to spot weld copper. Commercially pure copper sheets of 3 mm thickness were spot welded by FSSW using industrial friction stir welding machine. The spot welds were made by varying the tool rotational speed at three levels. The spot welds were characterized using optical microscopy. The shear fracture load was evaluated using a computerized tensile testing machine. The results revealed that the tool rotational speed remarkably influenced the microstructure, shear fracture load and mode of fracture.
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- Authors: Dinaharan, I. , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Copper , Friction stir spot welding , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/214059 , uj:21231 , Citation: Dinaharan, I & Akinlabi, E.T. 2016. Influence of tool rotational speed on microstructure and joint strength of friction stir spot welded pure copper.
- Description: Abstract: Copper is very difficult to be spot welded by conventional fusion welding techniques due to higher thermal diffusivity. Friction stir spot welding (FSSW) is a novel solid state welding process which is suitable and competent to spot weld copper. Commercially pure copper sheets of 3 mm thickness were spot welded by FSSW using industrial friction stir welding machine. The spot welds were made by varying the tool rotational speed at three levels. The spot welds were characterized using optical microscopy. The shear fracture load was evaluated using a computerized tensile testing machine. The results revealed that the tool rotational speed remarkably influenced the microstructure, shear fracture load and mode of fracture.
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Influence of scanning speed on the intermetallic produced in-situ in laser metal deposited TiC/Ti6Al4V composite
- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo
- Date: 2017
- Subjects: Laser Metal Deposition process , Microhardness , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/238164 , uj:24415 , Citation: Mahamood, R.M. & Akinlabi, E.T. 2017. Influence of scanning speed on the intermetallic produced in-situ in laser metal deposited TiC/Ti6Al4V composite.
- Description: Abstract: Effect of scanning speed on titanium aluminide-Ti3Al produced in-situ during laser metal deposited TiC/Ti6Al4V has been investigated and its effect on microhardness and wear resistance properties has been studied. In this study, titanium alloy –Ti6Al4V (an important aerospace alloy) was deposited in combination with titanium carbide-TiC using laser metal deposition process. The laser power was maintained at 3.2 kW throughout the deposition process. The powder flow rate and the gas flow rate were also kept at constant values of 2.88 g/min and 2 l/min respectively. The scanning speed was varied between 0.015 and 0.105 m/s , and the influence of the scanning speed on the titanium aluminide (Ti3Al) produced in-situ was studied and its effect on the wear resistance behaviour was also investigated. The study revealed that as the scanning speed was initially increased, the Ti3Al produced in-situ was found to increase and the wear resistance was found to improve. As the scanning speed was further increased beyond 0.06 m/s, the Ti3Al produced and the wear resistance were found to decrease.
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- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo
- Date: 2017
- Subjects: Laser Metal Deposition process , Microhardness , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/238164 , uj:24415 , Citation: Mahamood, R.M. & Akinlabi, E.T. 2017. Influence of scanning speed on the intermetallic produced in-situ in laser metal deposited TiC/Ti6Al4V composite.
- Description: Abstract: Effect of scanning speed on titanium aluminide-Ti3Al produced in-situ during laser metal deposited TiC/Ti6Al4V has been investigated and its effect on microhardness and wear resistance properties has been studied. In this study, titanium alloy –Ti6Al4V (an important aerospace alloy) was deposited in combination with titanium carbide-TiC using laser metal deposition process. The laser power was maintained at 3.2 kW throughout the deposition process. The powder flow rate and the gas flow rate were also kept at constant values of 2.88 g/min and 2 l/min respectively. The scanning speed was varied between 0.015 and 0.105 m/s , and the influence of the scanning speed on the titanium aluminide (Ti3Al) produced in-situ was studied and its effect on the wear resistance behaviour was also investigated. The study revealed that as the scanning speed was initially increased, the Ti3Al produced in-situ was found to increase and the wear resistance was found to improve. As the scanning speed was further increased beyond 0.06 m/s, the Ti3Al produced and the wear resistance were found to decrease.
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Influence of multi-pass friction stir processing on microstructure and mechanical properties of die cast Al-7Si-3Cu aluminium alloy
- Baruch, L. John, Raju, R., Balasubramanian, V., Rao, A.G., Dinaharan, I.
- Authors: Baruch, L. John , Raju, R. , Balasubramanian, V. , Rao, A.G. , Dinaharan, I.
- Date: 2016
- Subjects: Friction stir processing , Overlap multi-pass , Microstructure , Mechanical properties
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93804 , uj:20393 , Citation: Baruch, L.J. et al. 2016. Influence of multi-pass friction stir processing on microstructure and mechanical properties of die cast Al-7Si-3Cu aluminium alloy.
- Description: Abstract: The influence of overlap multi-pass friction stir processing on the microstructure and mechanical properties, in particular, strength, ductility and hardness of die cast Al-7Si-3Cu aluminium alloy was investigated. It was observed that with the increasing number of overlap passes friction stir processing resulted in significant refinement and redistribution of aluminium silicon eutectic phase with elimination of casting porosities. The microstructural refinement by the friction stir processing not only increases the ultimate tensile strength from 121to 273 MPa, but also increases the ductility as observed by the increase in fracture strain from 1.8% to 10%. Analysis of the fractured surface reveal that microstructural refinement obtained by friction stir processing plays a vital role in transforming the fracture mode from completely mixed mode to ductile mode of fracture with increasing number of passes. Change in the size, shape, morphology and distribution of eutectic silicon particles and elimination of porosities are the main reasons for the increase in tensile strength and ductility due to friction stir processing.
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- Authors: Baruch, L. John , Raju, R. , Balasubramanian, V. , Rao, A.G. , Dinaharan, I.
- Date: 2016
- Subjects: Friction stir processing , Overlap multi-pass , Microstructure , Mechanical properties
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93804 , uj:20393 , Citation: Baruch, L.J. et al. 2016. Influence of multi-pass friction stir processing on microstructure and mechanical properties of die cast Al-7Si-3Cu aluminium alloy.
- Description: Abstract: The influence of overlap multi-pass friction stir processing on the microstructure and mechanical properties, in particular, strength, ductility and hardness of die cast Al-7Si-3Cu aluminium alloy was investigated. It was observed that with the increasing number of overlap passes friction stir processing resulted in significant refinement and redistribution of aluminium silicon eutectic phase with elimination of casting porosities. The microstructural refinement by the friction stir processing not only increases the ultimate tensile strength from 121to 273 MPa, but also increases the ductility as observed by the increase in fracture strain from 1.8% to 10%. Analysis of the fractured surface reveal that microstructural refinement obtained by friction stir processing plays a vital role in transforming the fracture mode from completely mixed mode to ductile mode of fracture with increasing number of passes. Change in the size, shape, morphology and distribution of eutectic silicon particles and elimination of porosities are the main reasons for the increase in tensile strength and ductility due to friction stir processing.
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Influence of laser power on improving the wear properties of laser deposited Ti-6Al-4V+B4C composite
- Erinosho, Mutiu F., Akinlabi, Esther Titilayo
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: Laser metal deposition , Microstructure , Wear measurement
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273312 , uj:29114 , Citation: Erinosho, M.F. & Akinlabi, E.T. 2018. Influence of laser power on improving the wear properties of laser deposited Ti-6Al-4V+B4C composite.
- Description: Abstract: Titanium and its alloys have possessed outstanding properties such as high specific strength, good oxidation and corrosion resistance; which have made them extensively suitable for use in the aeronautical, medical, automobile, marine and chemical industries. This paper presents the impact of laser power on the microstructure and the wear properties of titanium matrix Ti-6Al-4V+B4C composites. The laser powers were varied between 0.8 kW and 2.2 kW while keeping other contributing parameters constant. The microstructural effects were characterised with increasing α-Ti lamella and coarse Widmanstettan structures as the laser power was increased; alongside with the inclusion of 20 wt % of B4C. The mechanical action during wear test has created a loop shape with inner and outer radii on the surface of the laser deposited composites. The wear thickness, depth and COF were taken into cognisance; with sample C deposited at a laser power of 1.8 kW and scanning speed of 1 m/min having the lowest wear loss of 0.119 mm3. The substrate exhibited the shallowest wear depth and the reason is attributed the compressive nature of the material. The interlace of B4C in the titanium matrix has improved the properties the laser formed composites.
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Influence of laser power on improving the wear properties of laser deposited Ti-6Al-4V+B4C composite
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo
- Date: 2018
- Subjects: Laser metal deposition , Microstructure , Wear measurement
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273312 , uj:29114 , Citation: Erinosho, M.F. & Akinlabi, E.T. 2018. Influence of laser power on improving the wear properties of laser deposited Ti-6Al-4V+B4C composite.
- Description: Abstract: Titanium and its alloys have possessed outstanding properties such as high specific strength, good oxidation and corrosion resistance; which have made them extensively suitable for use in the aeronautical, medical, automobile, marine and chemical industries. This paper presents the impact of laser power on the microstructure and the wear properties of titanium matrix Ti-6Al-4V+B4C composites. The laser powers were varied between 0.8 kW and 2.2 kW while keeping other contributing parameters constant. The microstructural effects were characterised with increasing α-Ti lamella and coarse Widmanstettan structures as the laser power was increased; alongside with the inclusion of 20 wt % of B4C. The mechanical action during wear test has created a loop shape with inner and outer radii on the surface of the laser deposited composites. The wear thickness, depth and COF were taken into cognisance; with sample C deposited at a laser power of 1.8 kW and scanning speed of 1 m/min having the lowest wear loss of 0.119 mm3. The substrate exhibited the shallowest wear depth and the reason is attributed the compressive nature of the material. The interlace of B4C in the titanium matrix has improved the properties the laser formed composites.
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Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze
- Okoro, Avwerosuoghene Moses, Lephuthing, Senzeni Sipho, Oke, Samuel Ranti, Olubambi, Peter Apata
- Authors: Okoro, Avwerosuoghene Moses , Lephuthing, Senzeni Sipho , Oke, Samuel Ranti , Olubambi, Peter Apata
- Date: 2021
- Subjects: Spark plasma sintering , Nickel aluminium bronze , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480910 , uj:43551 , Citation: Okoro, A.M. et al. 2021. Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze. DOI: https://doi.org/10.1051/mfreview/2021006
- Description: Abstract: In this study, nickel aluminium bronze alloys (NAB) with appreciable densification and improved microhardness was consolidated via spark plasma sintering technique. The NAB alloy was synthesized from starting elemental powders comprised nickel (4 wt.%), aluminium (6, 8 & 10 wt.%) and copper using dry milling technique. Starting powders were homogeneously milled using gentle ball mill for 8 h at a speed of 150 rpm and a BPR of 10:1. Subsequently, the milled powders were consolidated using the spark plasma sintering technique at 750 °C under a compressive pressure of 50MPa and rate of heating (100 °C/min). Furthermore, the powders and sintered alloys were characterized using SEM and XRD to ascertain the microstructural and phase evolutions during the synthesis of the NAB. The density and microhardness of the alloys were further investigated to ascertain the integrity of the sintered alloys. The results indicated that the increase in aluminium content resulted in the formation of intermetallic and beta phases on the alloy after sintering and the microhardness of the alloys improved with the increase in aluminium content.
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- Authors: Okoro, Avwerosuoghene Moses , Lephuthing, Senzeni Sipho , Oke, Samuel Ranti , Olubambi, Peter Apata
- Date: 2021
- Subjects: Spark plasma sintering , Nickel aluminium bronze , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480910 , uj:43551 , Citation: Okoro, A.M. et al. 2021. Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze. DOI: https://doi.org/10.1051/mfreview/2021006
- Description: Abstract: In this study, nickel aluminium bronze alloys (NAB) with appreciable densification and improved microhardness was consolidated via spark plasma sintering technique. The NAB alloy was synthesized from starting elemental powders comprised nickel (4 wt.%), aluminium (6, 8 & 10 wt.%) and copper using dry milling technique. Starting powders were homogeneously milled using gentle ball mill for 8 h at a speed of 150 rpm and a BPR of 10:1. Subsequently, the milled powders were consolidated using the spark plasma sintering technique at 750 °C under a compressive pressure of 50MPa and rate of heating (100 °C/min). Furthermore, the powders and sintered alloys were characterized using SEM and XRD to ascertain the microstructural and phase evolutions during the synthesis of the NAB. The density and microhardness of the alloys were further investigated to ascertain the integrity of the sintered alloys. The results indicated that the increase in aluminium content resulted in the formation of intermetallic and beta phases on the alloy after sintering and the microhardness of the alloys improved with the increase in aluminium content.
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Gas flow rate and powder flow rate effect on properties of laser metal deposited Ti6Al4V
- Pityana, Sisa, Mahamood, Rasheedat M., Akinlabi, Esther Titilayo, Shukla, Mukul
- Authors: Pityana, Sisa , Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul
- Date: 2013
- Subjects: Gas flow rate , Microhardness , Microstructure , Powder flow rate , Laser metal deposition , Additive manufacturing technology
- Type: Article
- Identifier: uj:4849 , http://hdl.handle.net/10210/12516
- Description: Tracks of Ti6Al4V powder were deposited on Ti6Al4V substrate using Laser Metal Deposition (LMD) process, an Additive Manufacturing (AM) manufacturing technology, at a laser power and scanning speed maintained at 1.8 kW and 0.005 m/s respectively. The powder flow rate and the gas flow rate were varied to study their effect on the physical, metallurgical and mechanical properties of the deposits. The physical properties studied are: the track width, the track height and the deposit weight. The mechanical property studied is the Microhardness profiling using Microhardness indenter at a load of 500g and dwelling time of 15 μm. The metallurgical property studied is the microstructure using the Optical microscopy. This study revealed that as the powder flow rate was increased, the track width, track height and the deposit weight were increased while as the powder flow rate was increased, the track width, track height and the deposit weight decreased. The results are presented and discussed in detail.
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- Authors: Pityana, Sisa , Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul
- Date: 2013
- Subjects: Gas flow rate , Microhardness , Microstructure , Powder flow rate , Laser metal deposition , Additive manufacturing technology
- Type: Article
- Identifier: uj:4849 , http://hdl.handle.net/10210/12516
- Description: Tracks of Ti6Al4V powder were deposited on Ti6Al4V substrate using Laser Metal Deposition (LMD) process, an Additive Manufacturing (AM) manufacturing technology, at a laser power and scanning speed maintained at 1.8 kW and 0.005 m/s respectively. The powder flow rate and the gas flow rate were varied to study their effect on the physical, metallurgical and mechanical properties of the deposits. The physical properties studied are: the track width, the track height and the deposit weight. The mechanical property studied is the Microhardness profiling using Microhardness indenter at a load of 500g and dwelling time of 15 μm. The metallurgical property studied is the microstructure using the Optical microscopy. This study revealed that as the powder flow rate was increased, the track width, track height and the deposit weight were increased while as the powder flow rate was increased, the track width, track height and the deposit weight decreased. The results are presented and discussed in detail.
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Forming behaviour of steel sheets after mechanical and laser beam forming
- Akinlabi, Esther Titilayo, Shukla, M., Akinlabi, S. A., Kanyanga, S. B., Chizyuka, C. M.
- Authors: Akinlabi, Esther Titilayo , Shukla, M. , Akinlabi, S. A. , Kanyanga, S. B. , Chizyuka, C. M.
- Date: 2014
- Subjects: Laser beam forming , Mechanical forming , Microhardness , Microstructure , Tensile testing , Steel plates - Mechanical properties
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/379024 , uj:4998 , http://hdl.handle.net/10210/13136
- Description: This paper reports the influencing factors and the characteristic behaviour of steel plates during both the mechanical forming and laser beam forming processes. Samples of the steel sheets were mechanically bent to 120 mm curvatures using a 20 ton capacity eccentric mechanical press at room temperature and also with the laser beam using a 4.4 kW Nd: YAG laser system at a scan speed of 1.9 m/min, beam diameter of 12 mm, laser power of 1.7 kW at 25% beam overlap using argon for cooling the irradiated surfaces. The chemical composition of both the as-received material and the formed samples were analysed by emission spectroscopy to quantify the changes in the elemental composition. The result shows a percentage increase in the carbon after the mechanical and laser forming processes when compared to the parent material. This can be attributed to the enhancement resulting from the forming processes. The formed samples were further characterized through microstructure, microhardness and tensile tests. The microstructural characterisation of the samples revealed that the grains of the mechanically formed and laser formed components are elongated, it was also observed that there is an increase in the pearlite grains of the laser formed components resulting from the thermal heating during the laser process. The microhardness profiles of the formed components showed that there is a significant percentage increase in the Vickers microhardness values of the laser formed samples when compared to the mechanically formed samples and with respect to the parent material. The laser beam forming process can be considered a more appropriate forming process in terms of the resulting material properties in this regard.
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- Authors: Akinlabi, Esther Titilayo , Shukla, M. , Akinlabi, S. A. , Kanyanga, S. B. , Chizyuka, C. M.
- Date: 2014
- Subjects: Laser beam forming , Mechanical forming , Microhardness , Microstructure , Tensile testing , Steel plates - Mechanical properties
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/379024 , uj:4998 , http://hdl.handle.net/10210/13136
- Description: This paper reports the influencing factors and the characteristic behaviour of steel plates during both the mechanical forming and laser beam forming processes. Samples of the steel sheets were mechanically bent to 120 mm curvatures using a 20 ton capacity eccentric mechanical press at room temperature and also with the laser beam using a 4.4 kW Nd: YAG laser system at a scan speed of 1.9 m/min, beam diameter of 12 mm, laser power of 1.7 kW at 25% beam overlap using argon for cooling the irradiated surfaces. The chemical composition of both the as-received material and the formed samples were analysed by emission spectroscopy to quantify the changes in the elemental composition. The result shows a percentage increase in the carbon after the mechanical and laser forming processes when compared to the parent material. This can be attributed to the enhancement resulting from the forming processes. The formed samples were further characterized through microstructure, microhardness and tensile tests. The microstructural characterisation of the samples revealed that the grains of the mechanically formed and laser formed components are elongated, it was also observed that there is an increase in the pearlite grains of the laser formed components resulting from the thermal heating during the laser process. The microhardness profiles of the formed components showed that there is a significant percentage increase in the Vickers microhardness values of the laser formed samples when compared to the mechanically formed samples and with respect to the parent material. The laser beam forming process can be considered a more appropriate forming process in terms of the resulting material properties in this regard.
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Experimental evaluation of surface quality characteristics in laser machining of nickel-based superalloy
- Authors: Khan, Adam M. , Gupta, Kapil
- Date: 2019
- Subjects: Kerf , Laser , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/404309 , uj:33902 , Citation: Khan, A.M. & Gupta, K. 2019. Experimental evaluation of surface quality characteristics in laser machining of nickel-based superalloy.
- Description: Abstract: This paper reports the investigation results of CO2 laser cutting of Inconel 718 superalloy. Investigation on the effects of the two important laser parameters power and travel speed on machinability i.e. material removal rate, kerf wall inclination, and average surface roughness of Inconel 718 has been conducted. Increased kerf wall inclination has been found with slow travel speed and increasing power. Low power and high travel speed produced maximum material removal rate and minimum surface roughness. Premature state of fusion has advanced dross regime at a slow cutting speed of 3.3 m/min and leading to a surface roughness of 9.3 microns maximum. Dendrite structures were formed and changes in surface hardness were observed due to high travel speed. Therefore, based on the investigation, slow travel speed with appropriate laser power is recommended for the improved machinability and surface quality of Inconel 718 superalloys.
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- Authors: Khan, Adam M. , Gupta, Kapil
- Date: 2019
- Subjects: Kerf , Laser , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/404309 , uj:33902 , Citation: Khan, A.M. & Gupta, K. 2019. Experimental evaluation of surface quality characteristics in laser machining of nickel-based superalloy.
- Description: Abstract: This paper reports the investigation results of CO2 laser cutting of Inconel 718 superalloy. Investigation on the effects of the two important laser parameters power and travel speed on machinability i.e. material removal rate, kerf wall inclination, and average surface roughness of Inconel 718 has been conducted. Increased kerf wall inclination has been found with slow travel speed and increasing power. Low power and high travel speed produced maximum material removal rate and minimum surface roughness. Premature state of fusion has advanced dross regime at a slow cutting speed of 3.3 m/min and leading to a surface roughness of 9.3 microns maximum. Dendrite structures were formed and changes in surface hardness were observed due to high travel speed. Therefore, based on the investigation, slow travel speed with appropriate laser power is recommended for the improved machinability and surface quality of Inconel 718 superalloys.
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