Fracture location characterizations of dissimilar friction stir welds.
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2011
- Subjects: Fracture location , Friction stir welding , Intermetallics , Metallography
- Type: Article
- Identifier: uj:5322 , http://hdl.handle.net/10210/8230
- Description: This paper reports the tensile fracture location characterizations of dissimilar friction stir welds between 5754 aluminium alloy and C11000 copper. The welds were produced using three shoulder diameter tools; namely, 15, 18 and 25 mm by varying the process parameters. The rotational speeds considered were 600, 950 and 1200 rpm while the feed rates employed were 50, 150 and 300 mm/min to represent the low, medium and high settings respectively. The tensile fracture locations were evaluated using the optical microscope to identify the fracture locations and were characterized. It was observed that 70% of the tensile samples failed in the Thermo Mechanically Affected Zone (TMAZ) of copper at the weld joints. Further evaluation of the fracture surfaces of the pulled tensile samples revealed that welds with low Ultimate Tensile Strength either have defects or intermetallics present at their joint interfaces.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2011
- Subjects: Fracture location , Friction stir welding , Intermetallics , Metallography
- Type: Article
- Identifier: uj:5322 , http://hdl.handle.net/10210/8230
- Description: This paper reports the tensile fracture location characterizations of dissimilar friction stir welds between 5754 aluminium alloy and C11000 copper. The welds were produced using three shoulder diameter tools; namely, 15, 18 and 25 mm by varying the process parameters. The rotational speeds considered were 600, 950 and 1200 rpm while the feed rates employed were 50, 150 and 300 mm/min to represent the low, medium and high settings respectively. The tensile fracture locations were evaluated using the optical microscope to identify the fracture locations and were characterized. It was observed that 70% of the tensile samples failed in the Thermo Mechanically Affected Zone (TMAZ) of copper at the weld joints. Further evaluation of the fracture surfaces of the pulled tensile samples revealed that welds with low Ultimate Tensile Strength either have defects or intermetallics present at their joint interfaces.
- Full Text:
Laser beam forming of 3 mm steel plate and the evolving properties
- Akinlabi, Stephen, Shukla, Mukul, Akinlabi, Esther Titilayo, Tshilidzi, Marwala
- Authors: Akinlabi, Stephen , Shukla, Mukul , Akinlabi, Esther Titilayo , Tshilidzi, Marwala
- Date: 2011
- Subjects: Laser beam forming , Deformation , Elongated grains
- Type: Article
- Identifier: uj:5325 , ISSN 1307-6884 , http://hdl.handle.net/10210/8239
- Description: This paper reports the evolving properties of a 3 mm low carbon steel plate after Laser Beam Forming process (LBF) To achieve this objective, the chemical analyse material and the formed components were carried out and compared; thereafter both were characterized through microhardness profiling, microstructural evaluation and tensile testing. The chemical analyses showed an increase in the elemental concentration of the formed component when compared to the as received material; this can be attributed to the enhancement property of the LBF process. The Ultimate Tensile Strength (UTS) and the Vickers microhardness of the formed component shows an increase when compared to the as received material, this was attributed to strain hardening and grain refinement brought about by the LBF process. The microstructure of the as received steel consists of equiaxed ferrit and pearlite while that of the formed component exhibits elongated grains.
- Full Text:
- Authors: Akinlabi, Stephen , Shukla, Mukul , Akinlabi, Esther Titilayo , Tshilidzi, Marwala
- Date: 2011
- Subjects: Laser beam forming , Deformation , Elongated grains
- Type: Article
- Identifier: uj:5325 , ISSN 1307-6884 , http://hdl.handle.net/10210/8239
- Description: This paper reports the evolving properties of a 3 mm low carbon steel plate after Laser Beam Forming process (LBF) To achieve this objective, the chemical analyse material and the formed components were carried out and compared; thereafter both were characterized through microhardness profiling, microstructural evaluation and tensile testing. The chemical analyses showed an increase in the elemental concentration of the formed component when compared to the as received material; this can be attributed to the enhancement property of the LBF process. The Ultimate Tensile Strength (UTS) and the Vickers microhardness of the formed component shows an increase when compared to the as received material, this was attributed to strain hardening and grain refinement brought about by the LBF process. The microstructure of the as received steel consists of equiaxed ferrit and pearlite while that of the formed component exhibits elongated grains.
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Characterizing sunflower oil biodiesel blends as alternatives to fossil diesel
- Madyira, Daniel M., Nkomo, Zanele, Akinlabi, Esther Titilayo
- Authors: Madyira, Daniel M. , Nkomo, Zanele , Akinlabi, Esther Titilayo
- Date: 2012
- Subjects: Fossil diesel , Sunflower oil , Biodiesel
- Type: Article
- Identifier: uj:4666 , ISBN 978-988-19252-2-0 , http://hdl.handle.net/10210/10046
- Description: This paper reports on investigation into the feasibility of using sunflower oil based biodiesel blends as alternatives to fossil diesel fuel. The current global reliance on fossil fuels is coming to an end. This is driven on one hand by the dwindling global fossil fuel reserves and the understanding of the consequences of carbon accumulation in the atmosphere on the other. Dwindling reserves continue to drive global fuel prices upwards with negative effects on economic performance. Continued accumulation of carbon dioxide in the atmosphere is perceived to be responsible for the Greenhouse Gas (GHG) effect. This dual problem can be addressed by using alternative renewable fuel sources, which guarantee continued supply while maintaining global carbon neutrality. Biofuels are now largely recognized as viable options. Some of the challenges of using biodiesel in conventional diesel engines are their low density, which leads to low calorific value and acidity levels that threatens the structural integrity of the engine. Blending biodiesel with petroleum diesel can mitigate these effects and lead to better performing fuels. Fuel characterization is therefore essential to establishing notable similarities and differences between biodiesel and fossil diesel, and in determining optimum blending proportions for more effective use of biodiesels. In this investigation, biodiesel was produced from commercial sunflower cooking oil using the batch trans-esterification process with methanol in the presence of Sodium hydroxide catalyst. The characterization of the biodiesel was then conducted using Nuclear Magnetic Resonance (NMR), bomb calorimetry, acidity and flash point analysis, sulphur content tests and Gas Chromatography (GC). Blends ranging between 5% and 50% biodiesel concentration in Ultra-Low Sulphur Diesel (ULSD), in increments of 5% were analyzed. Results obtained confirmed that biodiesel has lower calorific value than ULSD, implying higher fuel consumption. The high flash point, almost at a temperature twice as high as that of ULSD, though advantageous for storage and transportation, results in poor ignition. The results also suggest that an increase in concentration of biodiesel leads to larger difference in properties between the blend and the ULSD. The pH value of biodiesel was found to be lower than that of ULSD which compromises engine structural integrity. Biodiesel’s chain length was found to contain an average of 19 carbons which makes it a viable option when compared to ULSD. Despite the relatively inferior properties measured, biodiesel still remains one of the most attractive fuel options.
- Full Text:
- Authors: Madyira, Daniel M. , Nkomo, Zanele , Akinlabi, Esther Titilayo
- Date: 2012
- Subjects: Fossil diesel , Sunflower oil , Biodiesel
- Type: Article
- Identifier: uj:4666 , ISBN 978-988-19252-2-0 , http://hdl.handle.net/10210/10046
- Description: This paper reports on investigation into the feasibility of using sunflower oil based biodiesel blends as alternatives to fossil diesel fuel. The current global reliance on fossil fuels is coming to an end. This is driven on one hand by the dwindling global fossil fuel reserves and the understanding of the consequences of carbon accumulation in the atmosphere on the other. Dwindling reserves continue to drive global fuel prices upwards with negative effects on economic performance. Continued accumulation of carbon dioxide in the atmosphere is perceived to be responsible for the Greenhouse Gas (GHG) effect. This dual problem can be addressed by using alternative renewable fuel sources, which guarantee continued supply while maintaining global carbon neutrality. Biofuels are now largely recognized as viable options. Some of the challenges of using biodiesel in conventional diesel engines are their low density, which leads to low calorific value and acidity levels that threatens the structural integrity of the engine. Blending biodiesel with petroleum diesel can mitigate these effects and lead to better performing fuels. Fuel characterization is therefore essential to establishing notable similarities and differences between biodiesel and fossil diesel, and in determining optimum blending proportions for more effective use of biodiesels. In this investigation, biodiesel was produced from commercial sunflower cooking oil using the batch trans-esterification process with methanol in the presence of Sodium hydroxide catalyst. The characterization of the biodiesel was then conducted using Nuclear Magnetic Resonance (NMR), bomb calorimetry, acidity and flash point analysis, sulphur content tests and Gas Chromatography (GC). Blends ranging between 5% and 50% biodiesel concentration in Ultra-Low Sulphur Diesel (ULSD), in increments of 5% were analyzed. Results obtained confirmed that biodiesel has lower calorific value than ULSD, implying higher fuel consumption. The high flash point, almost at a temperature twice as high as that of ULSD, though advantageous for storage and transportation, results in poor ignition. The results also suggest that an increase in concentration of biodiesel leads to larger difference in properties between the blend and the ULSD. The pH value of biodiesel was found to be lower than that of ULSD which compromises engine structural integrity. Biodiesel’s chain length was found to contain an average of 19 carbons which makes it a viable option when compared to ULSD. Despite the relatively inferior properties measured, biodiesel still remains one of the most attractive fuel options.
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Design of an innovative accelerant detector
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A., Isvarial, Milan
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A. , Isvarial, Milan
- Date: 2012
- Subjects: Accelerant detectors
- Type: Article
- Identifier: uj:5338 , ISSN 2010-3778 , http://hdl.handle.net/10210/8898
- Description: Today, canines are still used effectively in acceleration detection situation. However, this method is becoming impractical in modern age and a new automated replacement to the canine is required. This paper reports the design of an innovative accelerant detector. Designing an accelerant detector is a long process as is any design process; therefore, a solution to the need for a mobile, effective accelerant detector is hereby presented. The device is simple and efficient to ensure that any accelerant detection can be conducted quickly and easily. The design utilizes Ultra Violet (UV) light to detect the accelerant. When the UV light shines on an accelerant, the hydrocarbons in the accelerant emit florescence. The advantages of using the UV light to detect accelerant are also outlined in this paper. The mobility of the device is achieved by using a Direct Current (DC) motor to run tank tracks. Tank tracks were chosen as to ensure that the device will be mobile in the rough terrain of a fire site. The materials selected for the various parts are also presented. A Solid Works Simulation was also conducted on the stresses in the shafts and the results are presented. This design is an innovative solution which offers a user friendly interface. The design is also environmentally friendly, ecologically sound and safe to use.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A. , Isvarial, Milan
- Date: 2012
- Subjects: Accelerant detectors
- Type: Article
- Identifier: uj:5338 , ISSN 2010-3778 , http://hdl.handle.net/10210/8898
- Description: Today, canines are still used effectively in acceleration detection situation. However, this method is becoming impractical in modern age and a new automated replacement to the canine is required. This paper reports the design of an innovative accelerant detector. Designing an accelerant detector is a long process as is any design process; therefore, a solution to the need for a mobile, effective accelerant detector is hereby presented. The device is simple and efficient to ensure that any accelerant detection can be conducted quickly and easily. The design utilizes Ultra Violet (UV) light to detect the accelerant. When the UV light shines on an accelerant, the hydrocarbons in the accelerant emit florescence. The advantages of using the UV light to detect accelerant are also outlined in this paper. The mobility of the device is achieved by using a Direct Current (DC) motor to run tank tracks. Tank tracks were chosen as to ensure that the device will be mobile in the rough terrain of a fire site. The materials selected for the various parts are also presented. A Solid Works Simulation was also conducted on the stresses in the shafts and the results are presented. This design is an innovative solution which offers a user friendly interface. The design is also environmentally friendly, ecologically sound and safe to use.
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Effect of scanning speed on material efficiency of laser metal deposited Ti6Al4V
- Akinlabi, Esther Titilayo, Mahamood, Rasheedat M., Shukla, Mukul, Pityana, Sisa
- Authors: Akinlabi, Esther Titilayo , Mahamood, Rasheedat M. , Shukla, Mukul , Pityana, Sisa
- Date: 2012
- Subjects: Laser Metal Deposition Process , Material efficiency , Titanium alloy , Laser scanning speed
- Type: Article
- Identifier: uj:5337 , ISSN 2010-3778 , http://hdl.handle.net/10210/8880
- Description: The study of effect of laser scanning speed on material efficiency in Ti6Al4V application is very important because unspent powder is not reusable because of high temperature oxygen pick-up and contamination. This study carried out an extensive study on the effect of scanning speed on material efficiency by varying the speed between 0.01 to 0.1m/sec. The samples are wire brushed and cleaned with acetone after each deposition to remove un-melted particles from the surface of the deposit. The substrate is weighed before and after deposition. A formula was developed to calculate the material efficiency and the scanning speed was compared with the powder efficiency obtained. The results are presented and discussed. The study revealed that the optimum scanning speed exists for this study at 0.01m/sec, above and below which the powder efficiency will drop.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Mahamood, Rasheedat M. , Shukla, Mukul , Pityana, Sisa
- Date: 2012
- Subjects: Laser Metal Deposition Process , Material efficiency , Titanium alloy , Laser scanning speed
- Type: Article
- Identifier: uj:5337 , ISSN 2010-3778 , http://hdl.handle.net/10210/8880
- Description: The study of effect of laser scanning speed on material efficiency in Ti6Al4V application is very important because unspent powder is not reusable because of high temperature oxygen pick-up and contamination. This study carried out an extensive study on the effect of scanning speed on material efficiency by varying the speed between 0.01 to 0.1m/sec. The samples are wire brushed and cleaned with acetone after each deposition to remove un-melted particles from the surface of the deposit. The substrate is weighed before and after deposition. A formula was developed to calculate the material efficiency and the scanning speed was compared with the powder efficiency obtained. The results are presented and discussed. The study revealed that the optimum scanning speed exists for this study at 0.01m/sec, above and below which the powder efficiency will drop.
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Friction stir welding of dissimilar materials – statistical analysis of the weld data
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding
- Type: Article
- Identifier: uj:5336 , ISSN 2078-0966 , http://hdl.handle.net/10210/8879
- Description: This paper reports the results of statistical analysis conducted on the weld data obtained from friction stir welding of aluminium and copper. The welds were produced by varying the process parameters; the rotational speed was varied between 600 to 1200 rpm and the welding speed varied between 50 and 300 mm/min. The Statistica (version 9.0) statistical analysis software package was used to generate the scatter and surface plots relative to the experimental results obtained from the tensile testing and the FSW data. Regression analysis was also done on the weld data. It was found that the downward vertical force has a significant effect on the Ultimate Tensile Strength of the weld and a strong relationship exist between the heat input into the welds and the measured electrical resistivities of the welds.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding
- Type: Article
- Identifier: uj:5336 , ISSN 2078-0966 , http://hdl.handle.net/10210/8879
- Description: This paper reports the results of statistical analysis conducted on the weld data obtained from friction stir welding of aluminium and copper. The welds were produced by varying the process parameters; the rotational speed was varied between 600 to 1200 rpm and the welding speed varied between 50 and 300 mm/min. The Statistica (version 9.0) statistical analysis software package was used to generate the scatter and surface plots relative to the experimental results obtained from the tensile testing and the FSW data. Regression analysis was also done on the weld data. It was found that the downward vertical force has a significant effect on the Ultimate Tensile Strength of the weld and a strong relationship exist between the heat input into the welds and the measured electrical resistivities of the welds.
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Friction stir welding process : a green technology
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Green technology
- Type: Article
- Identifier: uj:5335 , ISSN 2010-3778 , http://hdl.handle.net/10210/8878
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in the United Kingdom in 1991 for butt and lap welding of metals and plastics. This paper highlights the benefits of friction stir welding process as an energy efficient and a green technology process in the field of welding. Compared to the other conventional welding processes, its benefits, typical applications and its use in joining similar and dissimilar materials are also presented.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Green technology
- Type: Article
- Identifier: uj:5335 , ISSN 2010-3778 , http://hdl.handle.net/10210/8878
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in the United Kingdom in 1991 for butt and lap welding of metals and plastics. This paper highlights the benefits of friction stir welding process as an energy efficient and a green technology process in the field of welding. Compared to the other conventional welding processes, its benefits, typical applications and its use in joining similar and dissimilar materials are also presented.
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Functionally graded material: an overview
- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo, Shukla, Mukul, Pityana, Sisa
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2012
- Subjects: Functionally graded material
- Type: Article
- Identifier: uj:5342 , ISSN 978-988-19252-2-0 , http://hdl.handle.net/10210/9887
- Description: Functionally Graded Material (FGM) belongs to a class of advanced material characterized by variation in properties as the dimension varies. The overall properties of FMG are unique and different from any of the individual material that forms it. There is a wide range of applications for FGM and it is expected to increase as the cost of material processing and fabrication processes are reduced by improving these processes. In this study, an overview of fabrication processes, area of application, some recent research studies and the need to focus more research effort on improving the most promising FGM fabrication method (solid freeform SFF) is presented. Improving the performance of SFF processes and extensive studies on material characterization on components produced will go a long way in bringing down the manufacturing cost of FGM and increase productivity in this regard.
- Full Text:
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2012
- Subjects: Functionally graded material
- Type: Article
- Identifier: uj:5342 , ISSN 978-988-19252-2-0 , http://hdl.handle.net/10210/9887
- Description: Functionally Graded Material (FGM) belongs to a class of advanced material characterized by variation in properties as the dimension varies. The overall properties of FMG are unique and different from any of the individual material that forms it. There is a wide range of applications for FGM and it is expected to increase as the cost of material processing and fabrication processes are reduced by improving these processes. In this study, an overview of fabrication processes, area of application, some recent research studies and the need to focus more research effort on improving the most promising FGM fabrication method (solid freeform SFF) is presented. Improving the performance of SFF processes and extensive studies on material characterization on components produced will go a long way in bringing down the manufacturing cost of FGM and increase productivity in this regard.
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Laser forming of titanium and its alloys – an overview
- Akinlabi, Esther Titilayo, Shukla, Mukul, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Shukla, Mukul , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Titanium , Titanium alloy , Laser beam forming
- Type: Article
- Identifier: uj:5334 , ISSN 2070-3740 , http://hdl.handle.net/10210/8877
- Description: Laser beam forming is a novel technique developed for the joining of metallic components. In this study, an overview of the laser beam forming process, areas of application, the basic mechanisms of the laser beam forming process, some recent research studies and the need to focus more research effort on improving the laser-material interaction of laser beam forming of titanium and its alloys are presented.
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- Authors: Akinlabi, Esther Titilayo , Shukla, Mukul , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Titanium , Titanium alloy , Laser beam forming
- Type: Article
- Identifier: uj:5334 , ISSN 2070-3740 , http://hdl.handle.net/10210/8877
- Description: Laser beam forming is a novel technique developed for the joining of metallic components. In this study, an overview of the laser beam forming process, areas of application, the basic mechanisms of the laser beam forming process, some recent research studies and the need to focus more research effort on improving the laser-material interaction of laser beam forming of titanium and its alloys are presented.
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Microstructural characterizations of dissimilar friction stir welds
- Akinlabi, Esther Titilayo, Reddy, Randall D., Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Reddy, Randall D. , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Scanning Electron Microscopy , Aluminum alloys , Copper
- Type: Article
- Identifier: uj:5332 , ISSN 2070-3740 , http://hdl.handle.net/10210/8871
- Description: This paper reports the microstructural characteristics of dissimilar friction stir welds between 5754 aluminium alloy and C11000 copper. Dissimilar Friction Stir Welds of 5754 aluminium and C11000 copper were produced by varying the rotational speeds between 600 and 1200 rpm and the feed rate between 50 and 300 mm/min. The welds were characterized through Scanning Electron Microscopy (SEM). The SEM analysis revealed the levels of metallurgical bonding achieved at the joint interfaces of the welds produced and it can be established that better metallurgical bonding and good mixing of both materials joined were achieved in welds produced at lower feed rates of 50 mm/min and 150 mm/min while defect population was found to be common in the welds produced at high feed rate of 300 mm/min.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Reddy, Randall D. , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Scanning Electron Microscopy , Aluminum alloys , Copper
- Type: Article
- Identifier: uj:5332 , ISSN 2070-3740 , http://hdl.handle.net/10210/8871
- Description: This paper reports the microstructural characteristics of dissimilar friction stir welds between 5754 aluminium alloy and C11000 copper. Dissimilar Friction Stir Welds of 5754 aluminium and C11000 copper were produced by varying the rotational speeds between 600 and 1200 rpm and the feed rate between 50 and 300 mm/min. The welds were characterized through Scanning Electron Microscopy (SEM). The SEM analysis revealed the levels of metallurgical bonding achieved at the joint interfaces of the welds produced and it can be established that better metallurgical bonding and good mixing of both materials joined were achieved in welds produced at lower feed rates of 50 mm/min and 150 mm/min while defect population was found to be common in the welds produced at high feed rate of 300 mm/min.
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Non-destructive testing of dissimilar friction stir welds
- Akinlabi, Esther Titilayo, Levy, Adrian C. S., Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Levy, Adrian C. S. , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Non-destructive testing , Aluminum alloys , Copper
- Type: Article
- Identifier: uj:5333 , ISSN 2078-0966 , http://hdl.handle.net/10210/8876
- Description: friction stir welds between 5754 aluminium alloy and C11000 copper. The Friction stir welds of 5754 aluminium alloy and C11000 copper were produced at different tool rotational speeds and feed rates. The tool rotational speed was varied between 600 and 1200 rpm while the feed rate was varied between 50 and 300 mm/min. The visual inspection and the x-ray radiographic testing techniques were employed to conduct the tests; these tests were conducted on the welds to ascertain the joint integrity before characterization to have an idea of the quality of the welds. No visual defects were observed on all the welds considered but the x-ray radiography technique revealed the presence of wormhole defects and discontinuities in some of the welds. It was found that the welds produced at 950 rpm with varied feed rates were the best quality welds produced and this was substantiated with the microstructural evaluation of the joint interface. It was found that these welds have good mixing and metallurgical bonding at the interfaces.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Levy, Adrian C. S. , Akinlabi, Stephen A.
- Date: 2012
- Subjects: Friction stir welding , Non-destructive testing , Aluminum alloys , Copper
- Type: Article
- Identifier: uj:5333 , ISSN 2078-0966 , http://hdl.handle.net/10210/8876
- Description: friction stir welds between 5754 aluminium alloy and C11000 copper. The Friction stir welds of 5754 aluminium alloy and C11000 copper were produced at different tool rotational speeds and feed rates. The tool rotational speed was varied between 600 and 1200 rpm while the feed rate was varied between 50 and 300 mm/min. The visual inspection and the x-ray radiographic testing techniques were employed to conduct the tests; these tests were conducted on the welds to ascertain the joint integrity before characterization to have an idea of the quality of the welds. No visual defects were observed on all the welds considered but the x-ray radiography technique revealed the presence of wormhole defects and discontinuities in some of the welds. It was found that the welds produced at 950 rpm with varied feed rates were the best quality welds produced and this was substantiated with the microstructural evaluation of the joint interface. It was found that these welds have good mixing and metallurgical bonding at the interfaces.
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Characterising the effect of springback on mechanically formed steel plates
- Akinlabi, Esther Titilayo, Matlou, Kagisho, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Matlou, Kagisho , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Mechanical forming , Springback
- Type: Article
- Identifier: uj:4724 , ISSN 2078-0958 , http://hdl.handle.net/10210/11549
- Description: In the bending operation, springback causes geometrical inaccuracies of bent parts. To curb springback, various factors such as bending parameters and material properties need to be considered. This paper reports the effects of springback on mechanically formed steel plates. Experimental work using circular bending was conducted to analyse the effect of springback on the formed steel sheets. The sheets were bent using a punch and die having a radius of curvature of 120 mm. In addition, the formed samples were characterized through microstructure, microhardness and tensile results. The results revealed an error due to springback of 4.24%. Furthermore, the Vickers microhardness of the formed samples compared to the parent materials shows an increase of 6% while the Ultimate Tensile Strength also increased by 7%. The effects of strain hardening resulting from the bending process led to the increased hardness and strength of the material. The formed samples had elongated grains when compared to the equiaxed grains of the parent material. The increase in the grains can be attributed to the stretching of the material during the bending process.
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- Authors: Akinlabi, Esther Titilayo , Matlou, Kagisho , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Mechanical forming , Springback
- Type: Article
- Identifier: uj:4724 , ISSN 2078-0958 , http://hdl.handle.net/10210/11549
- Description: In the bending operation, springback causes geometrical inaccuracies of bent parts. To curb springback, various factors such as bending parameters and material properties need to be considered. This paper reports the effects of springback on mechanically formed steel plates. Experimental work using circular bending was conducted to analyse the effect of springback on the formed steel sheets. The sheets were bent using a punch and die having a radius of curvature of 120 mm. In addition, the formed samples were characterized through microstructure, microhardness and tensile results. The results revealed an error due to springback of 4.24%. Furthermore, the Vickers microhardness of the formed samples compared to the parent materials shows an increase of 6% while the Ultimate Tensile Strength also increased by 7%. The effects of strain hardening resulting from the bending process led to the increased hardness and strength of the material. The formed samples had elongated grains when compared to the equiaxed grains of the parent material. The increase in the grains can be attributed to the stretching of the material during the bending process.
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Characterising the effects of sand blasting on formed steel samples
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A., Ogunmuyiwa, Enoch
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A. , Ogunmuyiwa, Enoch
- Date: 2013
- Subjects: Metal forming , Sand blasting , Ultimate tensile strength
- Type: Article
- Identifier: uj:4880 , http://hdl.handle.net/10210/12593
- Description: The present research study focuses on the investigation of the influence of sand blasting on formed mild steel samples. The investigation involved the examinations on the parent material and a sand blasted material. The results were compared to the mechanically formed materials (sand and non-sand blasted) as well as a laser formed material (sand and non-sand blasted). Each material was characterized for the grain sizes and hardness. The percentage change in the grain sizes was quantified and correlation to the microhardness values was established. The Ultimate Tensile Strength (UTS) of the materials was also quantified using the obtained hardness values. The investigations revealed that the sand blasting causes an increase in the Vickers microhardness values of all the materials which also led to an increase in the UTS. After the forming operation, the microstructure revealed elongated grains as compared to almost equiaxed obtained from the parent non-sand blasted materials.
- Full Text:
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A. , Ogunmuyiwa, Enoch
- Date: 2013
- Subjects: Metal forming , Sand blasting , Ultimate tensile strength
- Type: Article
- Identifier: uj:4880 , http://hdl.handle.net/10210/12593
- Description: The present research study focuses on the investigation of the influence of sand blasting on formed mild steel samples. The investigation involved the examinations on the parent material and a sand blasted material. The results were compared to the mechanically formed materials (sand and non-sand blasted) as well as a laser formed material (sand and non-sand blasted). Each material was characterized for the grain sizes and hardness. The percentage change in the grain sizes was quantified and correlation to the microhardness values was established. The Ultimate Tensile Strength (UTS) of the materials was also quantified using the obtained hardness values. The investigations revealed that the sand blasting causes an increase in the Vickers microhardness values of all the materials which also led to an increase in the UTS. After the forming operation, the microstructure revealed elongated grains as compared to almost equiaxed obtained from the parent non-sand blasted materials.
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Design of a support system for a re-configured milling machine to achieve friction stir welds
- Akinlabi, Esther Titilayo, Levy, Adrian C. S., Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Levy, Adrian C. S. , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Friction Stir Welding , Friction stir welds
- Type: Article
- Identifier: uj:4830 , ISSN 2078-0966 , http://hdl.handle.net/10210/12423
- Description: The detailed design of a clamping and support system for a reconfigured milling machine to produce friction stir welds is reported in this paper. Two different concepts were considered and subjected to performance evaluation. The selected design concept is expected to effectively clamp and support the workpiece during the process of friction stir welding to achieve a good integrity.
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- Authors: Akinlabi, Esther Titilayo , Levy, Adrian C. S. , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Friction Stir Welding , Friction stir welds
- Type: Article
- Identifier: uj:4830 , ISSN 2078-0966 , http://hdl.handle.net/10210/12423
- Description: The detailed design of a clamping and support system for a reconfigured milling machine to produce friction stir welds is reported in this paper. Two different concepts were considered and subjected to performance evaluation. The selected design concept is expected to effectively clamp and support the workpiece during the process of friction stir welding to achieve a good integrity.
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Designs of temperature measuring device for a re-configured milling machine
- Akinlabi, Esther Titilayo, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Friction stir welding , Milling machines
- Type: Article
- Identifier: uj:4876 , http://hdl.handle.net/10210/12552
- Description: The design of temperature measuring approach for a re-configured milling machine to produce friction stir welds is reported in this paper. The product design specifications for the redesigning of a milling machine were first outlined and the ranking criteria were determined. Three different concepts were generated for the temperature measurement on the reconfigured system and the preferred or the best concept was selected based on the set design ranking criteria. Further simulation and performance analysis was then conducted on the concept. The Infrared Thermography (IRT) concept was selected for the temperature measurement among other concepts generated because it is an ideal and most effective system of measurement in this regard.
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- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Friction stir welding , Milling machines
- Type: Article
- Identifier: uj:4876 , http://hdl.handle.net/10210/12552
- Description: The design of temperature measuring approach for a re-configured milling machine to produce friction stir welds is reported in this paper. The product design specifications for the redesigning of a milling machine were first outlined and the ranking criteria were determined. Three different concepts were generated for the temperature measurement on the reconfigured system and the preferred or the best concept was selected based on the set design ranking criteria. Further simulation and performance analysis was then conducted on the concept. The Infrared Thermography (IRT) concept was selected for the temperature measurement among other concepts generated because it is an ideal and most effective system of measurement in this regard.
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Effect of crystallographic orientation on the pitting corrosion resistance of laser surface melted AISI 304L austenitic stainless steel
- Krishnan, S., Dumbre, J., Bhatt, S., Akinlabi, Esther Titilayo, Ramalingam, R.
- Authors: Krishnan, S. , Dumbre, J. , Bhatt, S. , Akinlabi, Esther Titilayo , Ramalingam, R.
- Date: 2013
- Subjects: Laser melting , Stainless steel , Austenitic stainless steel , Corrosion resistance
- Type: Article
- Identifier: uj:4846 , http://hdl.handle.net/10210/12513
- Description: The localized corrosion behavior of laser surface melted 304L austenitic stainless steel was studied by potentiodynamic polarization test. The extent of improvement in corrosion resistance was governed by the preferred orientation and the percentage of delta ferrite present on the surface of the laser melted sample. It was established by orientation imaging microscopy that the highest pitting potential value was obtained when grains were oriented in the most close- packed [101] direction compared to the random distribution of the base metal and other laser surface melted samples oriented in [001] direction. The sample with lower percentage of ferrite had good pitting resistance.
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- Authors: Krishnan, S. , Dumbre, J. , Bhatt, S. , Akinlabi, Esther Titilayo , Ramalingam, R.
- Date: 2013
- Subjects: Laser melting , Stainless steel , Austenitic stainless steel , Corrosion resistance
- Type: Article
- Identifier: uj:4846 , http://hdl.handle.net/10210/12513
- Description: The localized corrosion behavior of laser surface melted 304L austenitic stainless steel was studied by potentiodynamic polarization test. The extent of improvement in corrosion resistance was governed by the preferred orientation and the percentage of delta ferrite present on the surface of the laser melted sample. It was established by orientation imaging microscopy that the highest pitting potential value was obtained when grains were oriented in the most close- packed [101] direction compared to the random distribution of the base metal and other laser surface melted samples oriented in [001] direction. The sample with lower percentage of ferrite had good pitting resistance.
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Effects of processing parameters on the corrosion properties of dissimilar friction stir welds of aluminium and copper
- Akinlabi, Esther Titilayo, Anthony, Andrews, Akinlabi, Stephen A.
- Authors: Akinlabi, Esther Titilayo , Anthony, Andrews , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Aluminium alloy , Copper , Corrosion , Friction stir welding
- Type: Article
- Identifier: uj:5019 , http://hdl.handle.net/10210/13159
- Description: The influence of friction stir welding processing parameters on dissimilar joints conducted between aluminium alloy (AA5754) and commercially pure copper (C11000) was studied. The welds were produced by varying the rotational speed from 600 to 1200 r/min and the feed rate from 50 to 300 mm/min. The resulting microstructure and the corrosion properties of the welds produced were studied. It was found that the joint interfacial regions of the welds were characterized by interlayers of aluminium and copper. The corrosion tests revealed that the corrosion resistance of the welds was improved as the rotational speed was increased. The corrosion rates of the welds compared to the base metals were improved compared with Cu and decreased slightly compared with the aluminium alloy. The lowest corrosion rate was obtained at welds produced at rotational speed of 950 r/min and feed rate of 300 mm/min which corresponds to a weld produced at a low heat input.
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- Authors: Akinlabi, Esther Titilayo , Anthony, Andrews , Akinlabi, Stephen A.
- Date: 2013
- Subjects: Aluminium alloy , Copper , Corrosion , Friction stir welding
- Type: Article
- Identifier: uj:5019 , http://hdl.handle.net/10210/13159
- Description: The influence of friction stir welding processing parameters on dissimilar joints conducted between aluminium alloy (AA5754) and commercially pure copper (C11000) was studied. The welds were produced by varying the rotational speed from 600 to 1200 r/min and the feed rate from 50 to 300 mm/min. The resulting microstructure and the corrosion properties of the welds produced were studied. It was found that the joint interfacial regions of the welds were characterized by interlayers of aluminium and copper. The corrosion tests revealed that the corrosion resistance of the welds was improved as the rotational speed was increased. The corrosion rates of the welds compared to the base metals were improved compared with Cu and decreased slightly compared with the aluminium alloy. The lowest corrosion rate was obtained at welds produced at rotational speed of 950 r/min and feed rate of 300 mm/min which corresponds to a weld produced at a low heat input.
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Experimental investigation of laser beam forming of titanium and statistical analysis of the effects of parameters on curvature
- Akinlabi, Stephen A., Akinlabi, Esther Titilayo
- Authors: Akinlabi, Stephen A. , Akinlabi, Esther Titilayo
- Date: 2013
- Subjects: Laser beam forming , Titanium alloys
- Type: Article
- Identifier: uj:4746 , ISSN 2078-0966 , http://hdl.handle.net/10210/11732
- Description: Laser beam forming, a non-contact manufacturing process has become a viable manufacturing process for shaping metallic components. The capability of laser beam forming and bending demands more experimental studies to identify an optimized parameter setting and the likely parameters influencing the formed curvature. This paper investigates experimental laser beam forming of Ti6Al4V titanium alloy using a 4.4 kW Nd: YAG laser and studied the effects of the process parameters on the formed curvature. It was established that an increase in both the laser beam power and the number of scan tracks reduces the radius of curvature in the formed sheets having a more dome shape. The scan speed on the other hand, achieved the same good curvature at a slower or reduced scan speed to allow enough laser – material interaction. Furthermore, both the ANOVA and the regression analysis confirmed the repeatability of the experimental data. A simple regression model was developed based on the known active parameters to determine approximate curvatures instead of running a series of experiments.
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- Authors: Akinlabi, Stephen A. , Akinlabi, Esther Titilayo
- Date: 2013
- Subjects: Laser beam forming , Titanium alloys
- Type: Article
- Identifier: uj:4746 , ISSN 2078-0966 , http://hdl.handle.net/10210/11732
- Description: Laser beam forming, a non-contact manufacturing process has become a viable manufacturing process for shaping metallic components. The capability of laser beam forming and bending demands more experimental studies to identify an optimized parameter setting and the likely parameters influencing the formed curvature. This paper investigates experimental laser beam forming of Ti6Al4V titanium alloy using a 4.4 kW Nd: YAG laser and studied the effects of the process parameters on the formed curvature. It was established that an increase in both the laser beam power and the number of scan tracks reduces the radius of curvature in the formed sheets having a more dome shape. The scan speed on the other hand, achieved the same good curvature at a slower or reduced scan speed to allow enough laser – material interaction. Furthermore, both the ANOVA and the regression analysis confirmed the repeatability of the experimental data. A simple regression model was developed based on the known active parameters to determine approximate curvatures instead of running a series of experiments.
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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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Implementation of CMMS software for a maintenance plan in a manufacturing industry
- Aniki, Abimbola O., Akinlabi, Esther Titilayo
- Authors: Aniki, Abimbola O. , Akinlabi, Esther Titilayo
- Date: 2013
- Subjects: Computerized Maintenance Management System , Manufacturing industries
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/368875 , uj:4877 , http://hdl.handle.net/10210/12590
- Description: This paper proposes an effective maintenance method by considering the implementation of the Computerized Maintenance Management System (CMMS) software to plan a maintenance activity in a manufacturing industry. Globally, maintenance is a very important activity in the manufacturing sector to prolong the life span of equipment and machinery; it is also applicable to all household items. It is obvious and well known that apart from giving long life to equipment, it reduces the substantial financial losses for repairs and save the production downtime. In some cases, appropriate maintenance of plant equipment and machinery reduces the tendencies of injuries to personnel in the job floor. But before the maintenance process can be carried out, proper and effective work order planning and scheduling must be in place in other to achieve the set goals and objectives of a maintenance shop. Brief reviews of common planning tools which include the Computerized Maintenance Management System (CMMS) are presented. An interesting outline of analyses on planning and scheduling for effective job planning in a typical manufacturing industry using the CMMS is also presented and discussed. Finally, the steps to adhere to in making job planning effective in a manufacturing industry are also highlighted.
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- Authors: Aniki, Abimbola O. , Akinlabi, Esther Titilayo
- Date: 2013
- Subjects: Computerized Maintenance Management System , Manufacturing industries
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/368875 , uj:4877 , http://hdl.handle.net/10210/12590
- Description: This paper proposes an effective maintenance method by considering the implementation of the Computerized Maintenance Management System (CMMS) software to plan a maintenance activity in a manufacturing industry. Globally, maintenance is a very important activity in the manufacturing sector to prolong the life span of equipment and machinery; it is also applicable to all household items. It is obvious and well known that apart from giving long life to equipment, it reduces the substantial financial losses for repairs and save the production downtime. In some cases, appropriate maintenance of plant equipment and machinery reduces the tendencies of injuries to personnel in the job floor. But before the maintenance process can be carried out, proper and effective work order planning and scheduling must be in place in other to achieve the set goals and objectives of a maintenance shop. Brief reviews of common planning tools which include the Computerized Maintenance Management System (CMMS) are presented. An interesting outline of analyses on planning and scheduling for effective job planning in a typical manufacturing industry using the CMMS is also presented and discussed. Finally, the steps to adhere to in making job planning effective in a manufacturing industry are also highlighted.
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