Characterization of titanium alloy and boron carbide metal matrix composites (MMCS) for surface engineering applications
- Authors: Ogunlana, M.O.
- Date: 2016
- Subjects: Titanium alloys - Fatigue , Lasers - Industrial applications , Laser-induced breakdown spectroscopy , Pulsed laser deposition , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/212809 , uj:21030
- Description: Abstract: Surface engineering applications has brought titanium and its alloys into limelight in the manufacturing industries such as the aerospace, automobile, marine, food processing and chemical processing industry. Despite the growths experienced in the use of this material, Ti and its alloys are plagued with poor wear behaviour especially when in contact with other materials during application. This limitation of Ti-based components has led to a search for techniques and processes to modify, restructure and re-engineer such materials for extended lifespan and for reuse. Among various techniques for restoring and protecting the material is by the use of the laser metal deposition (LMD) technique otherwise called the laser cladding process. The LMD is a technique used to achieve a coating on components which allow the addition of reinforcing particles to improve the surface properties of titanium-based materials. These properties include hardness, wear amongst others. This research study involves the use of the LMD process to deposit composites coatings on titanium alloy (Ti6Al4V) substrate using Rofin Sinar 3.0 KW Ytterbium fibre laser system. The reinforcement titanium alloy (Ti6Al4V) and boron carbide (B4C) ceramic powder were employed to deposit Ti6Al4V-B4C composites coatings on Ti6Al4V substrate. The microstructural evaluation, geometrical analysis, porosity analysis, microhardness profiling and the wear characteristics of laser cladded composites were investigated. Samples from the as-deposited laser cladded composites were characterized using optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Both geometrical and porosity analyses were carried out to investigate the rate of dilution and defects such as porosity and cracks on the deposited composites coatings. Furthermore, performance characteristics were investigated using microhardness tester and CETRUMT-2 tribometer for the wear test analysis of the laser clad coatings of Ti6Al4V-B4C composites. This research work is also aimed to establish process parameters that will result in defect-free composite coatings. The microstructure of the Ti6Al4V-B4C composites revealed a pore and crack free clad when observed at laser power of 2200 W. The SEM analysis revealed that there is uniform distribution of the ceramic particles in the titanium matrix at higher laser power. The geometrical analysis of the samples revealed that the aspect ratio (AR) and the dilution (D) increases with an increase in the laser power. The results obtained further revealed the dilution of approximately between 34% and 46% with aspect ratio between 2.16 and 3.58 were the best in terms of defectology for the combined with acceptable geometrical characteristics. The EDS and the XRD results revealed that there is a relationship between intermetallic phase of α+β titanium alloy and boron carbide in which certain amount of peaks... , M.Ing. (Mechanical Engineering)
- Full Text:
- Authors: Ogunlana, M.O.
- Date: 2016
- Subjects: Titanium alloys - Fatigue , Lasers - Industrial applications , Laser-induced breakdown spectroscopy , Pulsed laser deposition , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/212809 , uj:21030
- Description: Abstract: Surface engineering applications has brought titanium and its alloys into limelight in the manufacturing industries such as the aerospace, automobile, marine, food processing and chemical processing industry. Despite the growths experienced in the use of this material, Ti and its alloys are plagued with poor wear behaviour especially when in contact with other materials during application. This limitation of Ti-based components has led to a search for techniques and processes to modify, restructure and re-engineer such materials for extended lifespan and for reuse. Among various techniques for restoring and protecting the material is by the use of the laser metal deposition (LMD) technique otherwise called the laser cladding process. The LMD is a technique used to achieve a coating on components which allow the addition of reinforcing particles to improve the surface properties of titanium-based materials. These properties include hardness, wear amongst others. This research study involves the use of the LMD process to deposit composites coatings on titanium alloy (Ti6Al4V) substrate using Rofin Sinar 3.0 KW Ytterbium fibre laser system. The reinforcement titanium alloy (Ti6Al4V) and boron carbide (B4C) ceramic powder were employed to deposit Ti6Al4V-B4C composites coatings on Ti6Al4V substrate. The microstructural evaluation, geometrical analysis, porosity analysis, microhardness profiling and the wear characteristics of laser cladded composites were investigated. Samples from the as-deposited laser cladded composites were characterized using optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Both geometrical and porosity analyses were carried out to investigate the rate of dilution and defects such as porosity and cracks on the deposited composites coatings. Furthermore, performance characteristics were investigated using microhardness tester and CETRUMT-2 tribometer for the wear test analysis of the laser clad coatings of Ti6Al4V-B4C composites. This research work is also aimed to establish process parameters that will result in defect-free composite coatings. The microstructure of the Ti6Al4V-B4C composites revealed a pore and crack free clad when observed at laser power of 2200 W. The SEM analysis revealed that there is uniform distribution of the ceramic particles in the titanium matrix at higher laser power. The geometrical analysis of the samples revealed that the aspect ratio (AR) and the dilution (D) increases with an increase in the laser power. The results obtained further revealed the dilution of approximately between 34% and 46% with aspect ratio between 2.16 and 3.58 were the best in terms of defectology for the combined with acceptable geometrical characteristics. The EDS and the XRD results revealed that there is a relationship between intermetallic phase of α+β titanium alloy and boron carbide in which certain amount of peaks... , M.Ing. (Mechanical Engineering)
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Laser power interaction effect on the evolving properties of laser metal-deposited titanium
- Authors: Nyoni, Ezekiel
- Date: 2015
- Subjects: Titanium powder , Pulsed laser deposition , Metal coating , Biomedical materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/58432 , uj:16450
- Description: Abstract: Titanium and its alloys are regarded as super alloys because of their ability to maintain high strength and light weight properties at elevated temperatures. Titanium has posed problems during its machining; as it always reacts with the machining tool at high temperatures, making it one of the most expensive metals to machine. It has been the interest of researchers to be able to use additive manufacturing methods in the fabrication of titanium; and the rise in the use of the Laser Metal Deposition process in the manufacturing of titanium has led to research studies in additive manufacturing. However, complex interrelationships exists between the processing parameters which lay a demand to optimise the parameters. There has also been a rise in the demand for the bone implants recently in the biomedical industry. The main implants on demand are the dental, knee and hip implants. However, the biocompatibility of the existing materials has been an issue for some time; as most of these materials become reactive in the body for long-term implantation. This has led to the development of titanium as a material for bioimplants. This research study presents a platform for analysing the laser power interaction effects on the evolving properties of commercially pure titanium during laser metal deposition tailored for biomedical applications. A set of preliminary studies was first conducted to establish the processing parameter window. A total of seven samples were fabricated by depositing titanium powder onto a Ti-6Al-4V base metal by varying the laser power from 400 to 1600 watts, whilst keeping all the other parameters constant. This was done to check how the laser power relates to the material properties of titanium; as the laser power is recognised as one of the most influential parameters on the evolving properties of laser deposited materials. The microhardness, microstructure, wear resistance and bio-compatibility tests were conducted for the material characterisation of this study. The optimized processing parameters obtained for this research study were: the spot size of 4 mm, powder flow rate of 2 rpm, gas flow rate of 2 l/min, and the scanning speed set at 0.002m/s. The microstructural evaluation revealed that the rate of dilution increased with an increase in the laser power. The increase in the dilution ratio tended to have negative effects on the wear resistance capabilities of the deposited materials. As the dilution increased, the wear resistance of the deposits decreased. This is attributed to the fact that the bond strength of the deposits decreases with an increase in the laser power. Also, the microstructural evaluation showed that finer martensitic... , M.Ing. (Mechanical Engineering)
- Full Text:
- Authors: Nyoni, Ezekiel
- Date: 2015
- Subjects: Titanium powder , Pulsed laser deposition , Metal coating , Biomedical materials
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/58432 , uj:16450
- Description: Abstract: Titanium and its alloys are regarded as super alloys because of their ability to maintain high strength and light weight properties at elevated temperatures. Titanium has posed problems during its machining; as it always reacts with the machining tool at high temperatures, making it one of the most expensive metals to machine. It has been the interest of researchers to be able to use additive manufacturing methods in the fabrication of titanium; and the rise in the use of the Laser Metal Deposition process in the manufacturing of titanium has led to research studies in additive manufacturing. However, complex interrelationships exists between the processing parameters which lay a demand to optimise the parameters. There has also been a rise in the demand for the bone implants recently in the biomedical industry. The main implants on demand are the dental, knee and hip implants. However, the biocompatibility of the existing materials has been an issue for some time; as most of these materials become reactive in the body for long-term implantation. This has led to the development of titanium as a material for bioimplants. This research study presents a platform for analysing the laser power interaction effects on the evolving properties of commercially pure titanium during laser metal deposition tailored for biomedical applications. A set of preliminary studies was first conducted to establish the processing parameter window. A total of seven samples were fabricated by depositing titanium powder onto a Ti-6Al-4V base metal by varying the laser power from 400 to 1600 watts, whilst keeping all the other parameters constant. This was done to check how the laser power relates to the material properties of titanium; as the laser power is recognised as one of the most influential parameters on the evolving properties of laser deposited materials. The microhardness, microstructure, wear resistance and bio-compatibility tests were conducted for the material characterisation of this study. The optimized processing parameters obtained for this research study were: the spot size of 4 mm, powder flow rate of 2 rpm, gas flow rate of 2 l/min, and the scanning speed set at 0.002m/s. The microstructural evaluation revealed that the rate of dilution increased with an increase in the laser power. The increase in the dilution ratio tended to have negative effects on the wear resistance capabilities of the deposited materials. As the dilution increased, the wear resistance of the deposits decreased. This is attributed to the fact that the bond strength of the deposits decreases with an increase in the laser power. Also, the microstructural evaluation showed that finer martensitic... , M.Ing. (Mechanical Engineering)
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Fabrication and characterization of functionally graded titanium alloy with commercially pure titanium and titanium carbide deposited by laser metal deposition technique
- Authors: Mdlalo, X. M.
- Date: 2015
- Subjects: Titanium alloys - Fatigue , Lasers - Industrial applications , Pulsed laser deposition , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/225271 , uj:22748
- Description: Abstract: Titanium and Titanium –based alloys have been used for aerospace materials for many years. Recently, those alloys are now being increasingly utilised for automotive, industrial, chemical, energy industries and consumer applications because of its excellent tensile and fatigue strength, corrosion resistance and high toughness- to- mass ratio, temperature strength and Young modulus’s values. However, despite these numerous applications, their general usages are often restricted because of limitations in mechanical properties and poor anti-friction properties exhibited in selected service conditions. There are different rapid solidification methods that have been put forward by some authors to address these deficiencies. Laser Metal Deposition has the potential to offer all specific solutions to key engineering problems over the traditional metal-working techniques. However, the purpose of this research work focuses on the laser metal deposition of CpTi /TiC composites coatings on Ti6A14V as a substrate by the laser melting of CpTi and TiC elemental powder mixtures. The process parameters involved with the LMD method include the laser power, traverse speed, powder-flow rate, and gas-flow rates. The characterization was done using OM, SEM, EDS, microhardness and tensile testing. The laser power was varied between 800W to 1600 W, while all the other parameters were kept constant. The results show that as laser power increases, the average hardness and the strength values also increase continuously. The results revealed that the microhardness values increases from 383 HV0.1 for the substrate and they reach a peak as high as 460 HV0.1 for sample A3 and the lowest value of 364 HV0.1 for sample A2. The tensile test showed that the average UTS for the four samples were 1545.18 MPa while the YTS and the percentage elongation were 932.60 MPa and 67% respectively. The average grain size of the substrate materials was determined to being 44.4 μm. The highest average grain size for sample A4 and lowest is for sample A1 of the deposited samples were found to be 79.8 μm and 67.7 μm respectively. , M.Ing. (Mechanical Engineering)
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- Authors: Mdlalo, X. M.
- Date: 2015
- Subjects: Titanium alloys - Fatigue , Lasers - Industrial applications , Pulsed laser deposition , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/225271 , uj:22748
- Description: Abstract: Titanium and Titanium –based alloys have been used for aerospace materials for many years. Recently, those alloys are now being increasingly utilised for automotive, industrial, chemical, energy industries and consumer applications because of its excellent tensile and fatigue strength, corrosion resistance and high toughness- to- mass ratio, temperature strength and Young modulus’s values. However, despite these numerous applications, their general usages are often restricted because of limitations in mechanical properties and poor anti-friction properties exhibited in selected service conditions. There are different rapid solidification methods that have been put forward by some authors to address these deficiencies. Laser Metal Deposition has the potential to offer all specific solutions to key engineering problems over the traditional metal-working techniques. However, the purpose of this research work focuses on the laser metal deposition of CpTi /TiC composites coatings on Ti6A14V as a substrate by the laser melting of CpTi and TiC elemental powder mixtures. The process parameters involved with the LMD method include the laser power, traverse speed, powder-flow rate, and gas-flow rates. The characterization was done using OM, SEM, EDS, microhardness and tensile testing. The laser power was varied between 800W to 1600 W, while all the other parameters were kept constant. The results show that as laser power increases, the average hardness and the strength values also increase continuously. The results revealed that the microhardness values increases from 383 HV0.1 for the substrate and they reach a peak as high as 460 HV0.1 for sample A3 and the lowest value of 364 HV0.1 for sample A2. The tensile test showed that the average UTS for the four samples were 1545.18 MPa while the YTS and the percentage elongation were 932.60 MPa and 67% respectively. The average grain size of the substrate materials was determined to being 44.4 μm. The highest average grain size for sample A4 and lowest is for sample A1 of the deposited samples were found to be 79.8 μm and 67.7 μm respectively. , M.Ing. (Mechanical Engineering)
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Characterization of laser metal deposited 17-4 PH stainless steel and tungsten composite for surface engineering applications
- Authors: Adeyemi, A.A.
- Date: 2018
- Subjects: Pulsed laser deposition , Metal coating , Metals - Mechanical properties , Lasers - Industrial applications , Stainless steel
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284734 , uj:30767
- Description: Abstract: 17-4 PH Stainless steel is a martensitic characterized precipitation hardened stainless steel with excellent mechanical properties that has been tailored to industrial applications such as aerospace, automobile, marine, food processing equipment, oil and gas industries and chemical processing industries. Despite the growth experienced in the use of this material, 17-4 PH stainless steels are prone to degradation due to long service use in applications that required extreme hardness and wear resistance. This limitation led to the research of property enhancement of the material using modern fabrication technique called laser metal deposition additive manufacturing technology. Laser metal deposition is a modern additive manufacturing technique used in fabricating physical components from the configuration of a 3D CAD data model using a high intensity laser beam while depositing metallic powder on a substrate one layer at a time. This process is flexible in its use as it allows addition of reinforcing particles to improve surface properties of a metallic material such as hardness and wear amongst others. This research study presents the use of laser metal deposition process to investigate the property enhancement of 17-4 PH stainless steel through various characterization process such as microstructural evaluation, microhardness and wear test. The deposition process was carried out using Rofin Sinar Ytterbium fibre laser system of laser capacity of 3.0 kW. The reinforcement material was 17-4 PH stainless steel and tungsten metallic powder deposited on 316 stainless steel substrate. The deposition process commenced firstly with a trial-run deposition of 5 samples with multiple-track of 17-4 PH stainless steel at 50% overlapping percentage on 316 stainless steel substrate to establish process window. The reason for the trial-run was to achieve a deposition with no defects such as pores and cracks. After this was achieved, 17-4 PH stainless steel metallic powder and tungsten metallic powder were now deposited in form of multiple track at 50% overlapping percentage at high laser power and low laser power of 2600 W and 1500 W at varied tungsten powder flow rate on 316 stainless steel substrate. The microstructural evaluation, geometrical analysis, microhardness profiling and wear resistance characteristics of the deposited composites were investigated. The microstructural evolution investigation was carried out using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Geometrical analysis was carried out on the deposited composite samples both at high and low laser power to investigate the extent of laser... , M.Ing. (Mechanical Engineering)
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- Authors: Adeyemi, A.A.
- Date: 2018
- Subjects: Pulsed laser deposition , Metal coating , Metals - Mechanical properties , Lasers - Industrial applications , Stainless steel
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284734 , uj:30767
- Description: Abstract: 17-4 PH Stainless steel is a martensitic characterized precipitation hardened stainless steel with excellent mechanical properties that has been tailored to industrial applications such as aerospace, automobile, marine, food processing equipment, oil and gas industries and chemical processing industries. Despite the growth experienced in the use of this material, 17-4 PH stainless steels are prone to degradation due to long service use in applications that required extreme hardness and wear resistance. This limitation led to the research of property enhancement of the material using modern fabrication technique called laser metal deposition additive manufacturing technology. Laser metal deposition is a modern additive manufacturing technique used in fabricating physical components from the configuration of a 3D CAD data model using a high intensity laser beam while depositing metallic powder on a substrate one layer at a time. This process is flexible in its use as it allows addition of reinforcing particles to improve surface properties of a metallic material such as hardness and wear amongst others. This research study presents the use of laser metal deposition process to investigate the property enhancement of 17-4 PH stainless steel through various characterization process such as microstructural evaluation, microhardness and wear test. The deposition process was carried out using Rofin Sinar Ytterbium fibre laser system of laser capacity of 3.0 kW. The reinforcement material was 17-4 PH stainless steel and tungsten metallic powder deposited on 316 stainless steel substrate. The deposition process commenced firstly with a trial-run deposition of 5 samples with multiple-track of 17-4 PH stainless steel at 50% overlapping percentage on 316 stainless steel substrate to establish process window. The reason for the trial-run was to achieve a deposition with no defects such as pores and cracks. After this was achieved, 17-4 PH stainless steel metallic powder and tungsten metallic powder were now deposited in form of multiple track at 50% overlapping percentage at high laser power and low laser power of 2600 W and 1500 W at varied tungsten powder flow rate on 316 stainless steel substrate. The microstructural evaluation, geometrical analysis, microhardness profiling and wear resistance characteristics of the deposited composites were investigated. The microstructural evolution investigation was carried out using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Geometrical analysis was carried out on the deposited composite samples both at high and low laser power to investigate the extent of laser... , M.Ing. (Mechanical Engineering)
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Fracture toughness characterisation of functionally graded grade 5 titanium alloy with titanium carbide
- Authors: Ratilal, Preyanka
- Date: 2016
- Subjects: Titanium alloys - Industrial applications , Titanium alloys - Fatigue , Lasers - Industrial applications , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/213532 , uj:21165
- Description: Abstract: Functionally graded materials (FGMs) are composites consisting of two or more different materials with a gradient composition. These materials are drawing attention because they can provide new combined functions that surpass the characteristics specific to its constituent elements. The aim of this research is to determine the effect of processing parameters on the fracture toughness of laser processed Ti-6Al-4V (Grade 5) with Titanium Carbide (TiC) to form FGM. Other characterisation tests were also conducted, which include the microstructure and microhardness. Titanium alloys have been chosen as the study material in this research work because titanium and its alloys have a high production cost and are difficult to machine. As a result, titanium has a low industrial usage although it has superior mechanical properties when compared to steel. Literature study has revealed limited information on the properties and characteristics of functionally graded Ti6Al4V and TiC, particularly the fracture toughness behaviour. Preliminary design was carried out to obtain optimised laser processing parameters. A total of 13 trials were carried out by varying the laser power (0.6 kW – 2.5 kW), the scanning speed (0.045 – 3 mm/min), laser spot size (2 or 4 mm) and the power flow rate (3.34 g/min or 6.68 g/min). The specimens were then characterised with respect to the evolving microstructure and the microhardness. For certain processing parameters, cracking of the FGM deposit was observed and could be heard during processing. Optimized laser parameters were obtained for laser power between 1.5 kW to 2.5 kW and scanning speed between 2.5 m/min to 3 m/min. Functionally graded grade 5 titanium (Ti6Al4V) with titanium carbide (TiC) was successfully prepared by laser metal deposition (LMD). The TiC fraction was varied from 5 to 40 vol. % in increments of 5 percentage. A total of 8 layers were deposited to form the FGM. The laser power was varied from 1.5 kW to 2.5 kW in increments of 0.5 kW. A total of 3 laser power settings consisting of 5 specimens each were prepared for fracture toughness testing. The FGM specimens were cut using wire electical discharge machining (WEDM) to obtain a compact specimen design for fracture toughness. An alternative method to fatigue pre-cracking was used to produce the pre-crack. WEDM was used as an alternative due to it being less costly compared to fatigue pre-cracking. Also investigations have proven that the fracture toughness measurements were satisfied according to the ASTM E 399-90 ... , M.Ing. (Mechanical Engineering)
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- Authors: Ratilal, Preyanka
- Date: 2016
- Subjects: Titanium alloys - Industrial applications , Titanium alloys - Fatigue , Lasers - Industrial applications , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/213532 , uj:21165
- Description: Abstract: Functionally graded materials (FGMs) are composites consisting of two or more different materials with a gradient composition. These materials are drawing attention because they can provide new combined functions that surpass the characteristics specific to its constituent elements. The aim of this research is to determine the effect of processing parameters on the fracture toughness of laser processed Ti-6Al-4V (Grade 5) with Titanium Carbide (TiC) to form FGM. Other characterisation tests were also conducted, which include the microstructure and microhardness. Titanium alloys have been chosen as the study material in this research work because titanium and its alloys have a high production cost and are difficult to machine. As a result, titanium has a low industrial usage although it has superior mechanical properties when compared to steel. Literature study has revealed limited information on the properties and characteristics of functionally graded Ti6Al4V and TiC, particularly the fracture toughness behaviour. Preliminary design was carried out to obtain optimised laser processing parameters. A total of 13 trials were carried out by varying the laser power (0.6 kW – 2.5 kW), the scanning speed (0.045 – 3 mm/min), laser spot size (2 or 4 mm) and the power flow rate (3.34 g/min or 6.68 g/min). The specimens were then characterised with respect to the evolving microstructure and the microhardness. For certain processing parameters, cracking of the FGM deposit was observed and could be heard during processing. Optimized laser parameters were obtained for laser power between 1.5 kW to 2.5 kW and scanning speed between 2.5 m/min to 3 m/min. Functionally graded grade 5 titanium (Ti6Al4V) with titanium carbide (TiC) was successfully prepared by laser metal deposition (LMD). The TiC fraction was varied from 5 to 40 vol. % in increments of 5 percentage. A total of 8 layers were deposited to form the FGM. The laser power was varied from 1.5 kW to 2.5 kW in increments of 0.5 kW. A total of 3 laser power settings consisting of 5 specimens each were prepared for fracture toughness testing. The FGM specimens were cut using wire electical discharge machining (WEDM) to obtain a compact specimen design for fracture toughness. An alternative method to fatigue pre-cracking was used to produce the pre-crack. WEDM was used as an alternative due to it being less costly compared to fatigue pre-cracking. Also investigations have proven that the fracture toughness measurements were satisfied according to the ASTM E 399-90 ... , M.Ing. (Mechanical Engineering)
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Advanced coating and surfacing : enhancement of surface integrity of laser metal deposited titanium alloy with copper
- Authors: Folorunsho, Erinosho Mutiu
- Date: 2015
- Subjects: Copper-titanium alloys , Metal coating
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/57249 , uj:16373
- Description: Abstract: Please refer to full text to view abstract , D.Ing. (Mechanical Engineering)
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- Authors: Folorunsho, Erinosho Mutiu
- Date: 2015
- Subjects: Copper-titanium alloys , Metal coating
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/57249 , uj:16373
- Description: Abstract: Please refer to full text to view abstract , D.Ing. (Mechanical Engineering)
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Experimental investigation and CFD modelling of laser metal deposited hybrid coating on grade five titanium alloy
- Authors: Gharehbaghi, Rezvan
- Date: 2018
- Subjects: Titanium alloys , Metal coating , Pulsed laser deposition , Computational fluid dynamics
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284286 , uj:30697
- Description: M.Ing. (Mechanical Engineering) , Abstract: The aim of this research project is to investigate the effect of laser deposited hybrid coatings (Al-Cu-Fe) on the physical, mechanical and metallurgical properties of titanium alloy (Ti-6Al-4V) by experimental techniques and numerical analysis. Laser Additive Manufacturing is relatively new in the manufacturing industry. Laser metal deposition (LMD) can be used to manufacture freeform shapes, to produce parts from graded porous to fully dense solid structures as well as to directly create various surface coatings on a part. This investigation also enhances the mechanical and corrosion properties of hybrid coatings of Al-Cu-Fe on Ti-6Al-4V alloy applicable in the aerospace industry through LMD technique. Icosahedral Al-Cu-Fe as quasicrystals are a relatively new class of materials which exhibit unusual atomic structure with useful physical and chemical properties. Ti6Al4V/Al-Cu-Fe composites were analysed using optical microscopy, scanning electron microscopy (SEM) with energy dispersive microscopy (EDS), indentation testing, x-ray diffraction (XRD) analysis. The hardness and wear resistance performances of the laser coatings were examined by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. The anti-corrosion performances were evaluated by linear polarization technique in 3.5 M NaCl. It was found that the geometrical properties (deposit width and height, heat affected zone (HAZ) height), dilution rate, aspect ratio and powder efficiency of each sample remarkably increased with increasing laser power due to the laser-material interaction. However, the geometrical properties decrease with increasing scanning speed. Solidification began with formation of some large particles such as Al and Fe. The atomic migration of Cu into Ti lattice resulted in the formation of β-Ti phase during cooling and travels a longer distance in the Ti lattice than other elements which opens more crystallographic structure of the β matrix. It was observed that there was higher number of titanium and aluminium presented in the composite as per the theoretical expectation. The indentation testing reveals that Ti6Al4V/Al-Cu-5Fe composite has the highest mean hardness value and it decreases with increasing laser power at scanning speed of 0.8 m/min and 1 m/min. The corrosion and wear resistance of titanium alloy was improved by depositing Al-Cu-Fe quasicrystalline coating. The results obtained from numerical simulation using CFD analysis demonstrated that Ti6Al4V/Al-Cu-10Fe has the highest dilution rate, aspect ratio and HAZ height, and this corresponded with the experimental results. Finally, it was found that Ti6Al4V/Al-Cu-Fe composite have useful mechanical, physical and...
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- Authors: Gharehbaghi, Rezvan
- Date: 2018
- Subjects: Titanium alloys , Metal coating , Pulsed laser deposition , Computational fluid dynamics
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/284286 , uj:30697
- Description: M.Ing. (Mechanical Engineering) , Abstract: The aim of this research project is to investigate the effect of laser deposited hybrid coatings (Al-Cu-Fe) on the physical, mechanical and metallurgical properties of titanium alloy (Ti-6Al-4V) by experimental techniques and numerical analysis. Laser Additive Manufacturing is relatively new in the manufacturing industry. Laser metal deposition (LMD) can be used to manufacture freeform shapes, to produce parts from graded porous to fully dense solid structures as well as to directly create various surface coatings on a part. This investigation also enhances the mechanical and corrosion properties of hybrid coatings of Al-Cu-Fe on Ti-6Al-4V alloy applicable in the aerospace industry through LMD technique. Icosahedral Al-Cu-Fe as quasicrystals are a relatively new class of materials which exhibit unusual atomic structure with useful physical and chemical properties. Ti6Al4V/Al-Cu-Fe composites were analysed using optical microscopy, scanning electron microscopy (SEM) with energy dispersive microscopy (EDS), indentation testing, x-ray diffraction (XRD) analysis. The hardness and wear resistance performances of the laser coatings were examined by high diamond dura scan microhardness tester and CERT UMT-2 reciprocating sliding machine. The anti-corrosion performances were evaluated by linear polarization technique in 3.5 M NaCl. It was found that the geometrical properties (deposit width and height, heat affected zone (HAZ) height), dilution rate, aspect ratio and powder efficiency of each sample remarkably increased with increasing laser power due to the laser-material interaction. However, the geometrical properties decrease with increasing scanning speed. Solidification began with formation of some large particles such as Al and Fe. The atomic migration of Cu into Ti lattice resulted in the formation of β-Ti phase during cooling and travels a longer distance in the Ti lattice than other elements which opens more crystallographic structure of the β matrix. It was observed that there was higher number of titanium and aluminium presented in the composite as per the theoretical expectation. The indentation testing reveals that Ti6Al4V/Al-Cu-5Fe composite has the highest mean hardness value and it decreases with increasing laser power at scanning speed of 0.8 m/min and 1 m/min. The corrosion and wear resistance of titanium alloy was improved by depositing Al-Cu-Fe quasicrystalline coating. The results obtained from numerical simulation using CFD analysis demonstrated that Ti6Al4V/Al-Cu-10Fe has the highest dilution rate, aspect ratio and HAZ height, and this corresponded with the experimental results. Finally, it was found that Ti6Al4V/Al-Cu-Fe composite have useful mechanical, physical and...
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Property enhancement of aerospace grade titanium alloy (Ti6Al4V) by laser metal deposition
- Authors: Moolla, Muhammad
- Date: 2017
- Subjects: Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/286077 , uj:30949
- Description: M.Ing. (Mechanical Engineering) , Abstract: Laser metal deposition (LMD) presents a competitive and attractive single stage process for producing complex shapes in typically difficult to machined materials like titanium alloys compared to the traditional machining process. It specifically provides incentives for the production of components with improved surface properties for enhanced lifetime performance in aerospace, defense, marine and power applications. But, a major complexity in the process is the lack of complete understanding of the influence of some laser processing parameters on the production of defect-free metal deposits on substrate metallic workpiece. Therefore, in this research, an attempt was made to explore LMD for the deposition of Ti + TiB2 powders on aerospace grade titanium alloy for improved wear and corrosion resistance properties using different powder compositions of Ti + TiB2 at a constant laser power, scanning speed and beam spot size. Microstructural analysis of the deposited composite samples indicated that LMD at a high powder composition of Ti in the range of 50 % to 90% of Ti powder produced a larger heat affected zone, high dilution ratio, and lower porosity because of the greater interaction between the laser beam and the workpiece; whereas higher powder composition of TiB2 powder in the range of 70 % to 100 % and low laser power generated a smaller heat affected zone. There was an incomplete melting of the deposited composites; which have resulted in poor physical, mechanical, metallurgical and corrosion properties due to the high percentage of TiB2. widmanstätten structures were equally apparent in these conditions due to the high cooling rate associated with the laser melting. Microhardness of the laser deposited composite produced at a powder composition of 50 % Ti + 50% TiB2 was increased by 219 % whilst the wear rate was improved by 682 % compared to the Ti6Al4V alloy substrate and the other laser deposited samples. The corrosion resistance under this condition was equally improved by 89 % in seawater corrosive medium. The results further showed that as the proportion TiB2 powder increases, the volume of deposit was decreased due to the small particle size of the TiB2 powder. However, this has led to the reduction in physical, mechanical and metallurgical properties. On the contrary, at a low composition of TiB2 powder, a high-quality deposit is produced. Therefore, the powder composition at 50 % Ti + 50 % TiB2 was established as the optimum composition for the deposition of defect-free Ti + TiB2 composite on aerospace grade titanium alloy for improved surface properties. Thus, a new composite material with enhanced physical, mechanical and metallurgical properties was successfully deposited on titanium alloy...
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- Authors: Moolla, Muhammad
- Date: 2017
- Subjects: Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/286077 , uj:30949
- Description: M.Ing. (Mechanical Engineering) , Abstract: Laser metal deposition (LMD) presents a competitive and attractive single stage process for producing complex shapes in typically difficult to machined materials like titanium alloys compared to the traditional machining process. It specifically provides incentives for the production of components with improved surface properties for enhanced lifetime performance in aerospace, defense, marine and power applications. But, a major complexity in the process is the lack of complete understanding of the influence of some laser processing parameters on the production of defect-free metal deposits on substrate metallic workpiece. Therefore, in this research, an attempt was made to explore LMD for the deposition of Ti + TiB2 powders on aerospace grade titanium alloy for improved wear and corrosion resistance properties using different powder compositions of Ti + TiB2 at a constant laser power, scanning speed and beam spot size. Microstructural analysis of the deposited composite samples indicated that LMD at a high powder composition of Ti in the range of 50 % to 90% of Ti powder produced a larger heat affected zone, high dilution ratio, and lower porosity because of the greater interaction between the laser beam and the workpiece; whereas higher powder composition of TiB2 powder in the range of 70 % to 100 % and low laser power generated a smaller heat affected zone. There was an incomplete melting of the deposited composites; which have resulted in poor physical, mechanical, metallurgical and corrosion properties due to the high percentage of TiB2. widmanstätten structures were equally apparent in these conditions due to the high cooling rate associated with the laser melting. Microhardness of the laser deposited composite produced at a powder composition of 50 % Ti + 50% TiB2 was increased by 219 % whilst the wear rate was improved by 682 % compared to the Ti6Al4V alloy substrate and the other laser deposited samples. The corrosion resistance under this condition was equally improved by 89 % in seawater corrosive medium. The results further showed that as the proportion TiB2 powder increases, the volume of deposit was decreased due to the small particle size of the TiB2 powder. However, this has led to the reduction in physical, mechanical and metallurgical properties. On the contrary, at a low composition of TiB2 powder, a high-quality deposit is produced. Therefore, the powder composition at 50 % Ti + 50 % TiB2 was established as the optimum composition for the deposition of defect-free Ti + TiB2 composite on aerospace grade titanium alloy for improved surface properties. Thus, a new composite material with enhanced physical, mechanical and metallurgical properties was successfully deposited on titanium alloy...
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Advanced material development : functionally graded stainless steel alloy composites
- Authors: Bayode, A.
- Date: 2018
- Subjects: Metallic composites , Metal coating , Pulsed laser deposition
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/284879 , uj:30784
- Description: D.Ing. (Mechanical Engineering) , Abstract: Laser metal deposition (LMD) is one of the additive manufacturing technologies that is used in the production of fully dense parts layer by layer. This innovative manufacturing process shows real promise in reducing component fabrication time, cost and weight. One of the major advantages of this technology is in the ability to manufacture components with multi-material properties such as Functionally Graded Materials (FGM). FGM is a class of advanced materials that combine the benefits of its component materials together as a whole, while minimizing the problems produced by material property mismatch of the constituent materials. Several studies have been conducted on FGMs processed by LMD. Most of these studies are on metal-ceramic composites, however, there is a growing need for bimetallic components with different properties along their axial or radial directions for modern engineering applications. In this study, the laser metal deposition process was evaluated as a candidate for manufacturing a compositionally graded bimetal material consisting magnetic and non-magnetic metals. The materials used were 17-4PH powder, AISI 316L powder and AISI 316 substrate. Since this study has not been done and there were no known models or strategies to follow in building this particular FGM. Trial and error experiments were first adopted in selecting the process conditions for building the FGM. The trial and error experiments, referred to as preliminary study involved the production of 17- 4PH and AISI 316L clads. This was done primarily to evaluate the solidification behaviour of the individual powders and also identify the process window that will successfully produce fully dense clads with good bonding and wettability that are structurally harmonised. Based on the findings of the preliminary studies, a set of parameters was obtained as a standard for producing the compositionally graded composite...
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- Authors: Bayode, A.
- Date: 2018
- Subjects: Metallic composites , Metal coating , Pulsed laser deposition
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/284879 , uj:30784
- Description: D.Ing. (Mechanical Engineering) , Abstract: Laser metal deposition (LMD) is one of the additive manufacturing technologies that is used in the production of fully dense parts layer by layer. This innovative manufacturing process shows real promise in reducing component fabrication time, cost and weight. One of the major advantages of this technology is in the ability to manufacture components with multi-material properties such as Functionally Graded Materials (FGM). FGM is a class of advanced materials that combine the benefits of its component materials together as a whole, while minimizing the problems produced by material property mismatch of the constituent materials. Several studies have been conducted on FGMs processed by LMD. Most of these studies are on metal-ceramic composites, however, there is a growing need for bimetallic components with different properties along their axial or radial directions for modern engineering applications. In this study, the laser metal deposition process was evaluated as a candidate for manufacturing a compositionally graded bimetal material consisting magnetic and non-magnetic metals. The materials used were 17-4PH powder, AISI 316L powder and AISI 316 substrate. Since this study has not been done and there were no known models or strategies to follow in building this particular FGM. Trial and error experiments were first adopted in selecting the process conditions for building the FGM. The trial and error experiments, referred to as preliminary study involved the production of 17- 4PH and AISI 316L clads. This was done primarily to evaluate the solidification behaviour of the individual powders and also identify the process window that will successfully produce fully dense clads with good bonding and wettability that are structurally harmonised. Based on the findings of the preliminary studies, a set of parameters was obtained as a standard for producing the compositionally graded composite...
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Characterising laser metal deposited titanium and molybdenum on titanium alloy for surface engineering applications
- Authors: Ntumba, Eric Muipatay
- Date: 2016
- Subjects: Laser-induced breakdown spectroscopy , Pulsed laser deposition , Lasers - Industrial applications , Titanium powder , Metal coating , Molybdenum
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/212802 , uj:21029
- Description: Abstract: In this work, sample study was done on the characterisation of Ti-10%Mo powder metal produced via LMD. Different process parameters were employed for the LMD process. The laser power was varied between 1kW and 2.2kW while keeping all other parameters constant. The scanning speed of 0.5m/sec, powder flow rate of pure titanium 1.8g/min and the powder flow rate of molybdenum 2g/min. were used for the coatings. The process parameters were carefully selected to represent low, medium and high settings. The characterisations carried out include optical microscopy and Scanning Electron Microscopy combined with Energy Dispersive Spectroscopy (SEM/EDS) techniques to investigate the particle distribution, microstructural evolution and chemical analysis of the welded samples. Vickers microhardness was used to determine the hardness distribution of the coating Ti6Al4V/Ti-Mo, the dry sliding wear tests were carried out on the deposited Ti6Al4V/Ti-Mo samples to determine the sliding wear of samples and corrosion tests was used to obtain information on the corrosion behavior of Ti6Al4V/Ti-Mo in 3.5% NaCl solution. The characterised laser metal deposited Ti6Al4V and Ti-Mo, revealed that the varied laser power played a main part in the microstructural evolution. It was found that the formation of the Widmanstӓtten structures improved the hardness of Ti6Al4V/Ti-Mo. The highest hardness value was found at the top zone of the clad owing to the presence of the reinforcement particles of Ti-Mo, the highest hardness value for all the samples was found at an average of 496HV. The sample produced at a laser power of 2kW and scanning speed of 0.5m/sec was found to show the lowest percentage of wear volume and the sample produced at laser power of 1.4kW and scanning speed of 0.5m/sec had the lowest percentage of the coefficient of friction; and this outcome can be attributed to the martensitic structure formed during cooling. The results obtained showed that the poor wear behaviour of the titanium alloy has been improved with the addition of Ti-Mo into their lattices. The experimental results indicated that the corrosion rate of the developed composites decreased significantly with the addition of the Ti-Mo powder. The results obtained from the polarization behavior show a decrease in the polarization resistance. While the open-circuit potential (OCP) for the alloy was found to reduce with time due to oxide film thickening on the metal surface... , M.Ing. (Mechanical Engineering Science)
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- Authors: Ntumba, Eric Muipatay
- Date: 2016
- Subjects: Laser-induced breakdown spectroscopy , Pulsed laser deposition , Lasers - Industrial applications , Titanium powder , Metal coating , Molybdenum
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/212802 , uj:21029
- Description: Abstract: In this work, sample study was done on the characterisation of Ti-10%Mo powder metal produced via LMD. Different process parameters were employed for the LMD process. The laser power was varied between 1kW and 2.2kW while keeping all other parameters constant. The scanning speed of 0.5m/sec, powder flow rate of pure titanium 1.8g/min and the powder flow rate of molybdenum 2g/min. were used for the coatings. The process parameters were carefully selected to represent low, medium and high settings. The characterisations carried out include optical microscopy and Scanning Electron Microscopy combined with Energy Dispersive Spectroscopy (SEM/EDS) techniques to investigate the particle distribution, microstructural evolution and chemical analysis of the welded samples. Vickers microhardness was used to determine the hardness distribution of the coating Ti6Al4V/Ti-Mo, the dry sliding wear tests were carried out on the deposited Ti6Al4V/Ti-Mo samples to determine the sliding wear of samples and corrosion tests was used to obtain information on the corrosion behavior of Ti6Al4V/Ti-Mo in 3.5% NaCl solution. The characterised laser metal deposited Ti6Al4V and Ti-Mo, revealed that the varied laser power played a main part in the microstructural evolution. It was found that the formation of the Widmanstӓtten structures improved the hardness of Ti6Al4V/Ti-Mo. The highest hardness value was found at the top zone of the clad owing to the presence of the reinforcement particles of Ti-Mo, the highest hardness value for all the samples was found at an average of 496HV. The sample produced at a laser power of 2kW and scanning speed of 0.5m/sec was found to show the lowest percentage of wear volume and the sample produced at laser power of 1.4kW and scanning speed of 0.5m/sec had the lowest percentage of the coefficient of friction; and this outcome can be attributed to the martensitic structure formed during cooling. The results obtained showed that the poor wear behaviour of the titanium alloy has been improved with the addition of Ti-Mo into their lattices. The experimental results indicated that the corrosion rate of the developed composites decreased significantly with the addition of the Ti-Mo powder. The results obtained from the polarization behavior show a decrease in the polarization resistance. While the open-circuit potential (OCP) for the alloy was found to reduce with time due to oxide film thickening on the metal surface... , M.Ing. (Mechanical Engineering Science)
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Experimental and surface analyses of laser deposited Al-Sn-Cu-Si coatings on Ti-6Al-4V alloy
- Authors: Obiegbu, Mary-Jane Chinenye
- Date: 2019
- Subjects: Metal coating , Protective coatings , Alloys - Mechanical properties , Lasers - Industrial applications
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/479347 , uj:43352
- Description: Abstract: Modification of surfaces is very necessary in order to mitigate against catastrophic surface degradation of wear and corrosion. The one solution against this aforementioned degradation is to design coatings that can fight against this menace in order to retain the surface integrity. These fabricated coatings would bring innovative microstructures with exceptional properties and performance. The inability of conventional techniques to fabricate complex designs, shapes and enhanced microstructures have led to Additive Manufacturing (A.M) techniques in seeking for solution to this problem. The project sought to utilize laser cladding of Ti-6Al-4V alloy as a method of improving its surface properties therefore expanding the range of applications and lifespan of the material... , M.Ing. (Mechanical Engineering Science)
- Full Text:
- Authors: Obiegbu, Mary-Jane Chinenye
- Date: 2019
- Subjects: Metal coating , Protective coatings , Alloys - Mechanical properties , Lasers - Industrial applications
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/479347 , uj:43352
- Description: Abstract: Modification of surfaces is very necessary in order to mitigate against catastrophic surface degradation of wear and corrosion. The one solution against this aforementioned degradation is to design coatings that can fight against this menace in order to retain the surface integrity. These fabricated coatings would bring innovative microstructures with exceptional properties and performance. The inability of conventional techniques to fabricate complex designs, shapes and enhanced microstructures have led to Additive Manufacturing (A.M) techniques in seeking for solution to this problem. The project sought to utilize laser cladding of Ti-6Al-4V alloy as a method of improving its surface properties therefore expanding the range of applications and lifespan of the material... , M.Ing. (Mechanical Engineering Science)
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Synthesis, CFD simulation and characterization of direct laser metal deposition (LMD) of Al-Cu-Ti coatings on Ti-6Al-4V alloy for aerospace application
- Authors: Lasisi, Adedoyin Michael
- Date: 2020
- Subjects: Lasers in aeronautics , Lasers - Industrial applications , Alloys - Mechanical properties , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/479570 , uj:43384
- Description: Abstract: This research study was aimed at researching the synthesis, simulation and characterization of Direct Laser Metal Deposition (DLMD) of Al-Cu-Ti Coatings on Ti-6Al- 4V Alloy for aerospace application. This investigation was accomplished by numerical analysis and experimental techniques. In the category of manufacturing techniques (Additive Manufacturing), the Direct Laser Metal Deposition (DLMD) technique is quite a new field in the industry. This manufacturing technique is flexible, in the sense that it can be used to manufacture working parts or components for bigger assemblies, freeform shapes according to the designer specifications, advanced coatings on the surfaces of working components, and fully solid structures. This research also enquires into the enhanced properties (mechanical, hardness and corrosion) of the modified coating powders (Al-Cu-Ti) on the Titanium alloy (Ti-6Al-4V) and its applications for components and parts enhancements in aerospace industries... , M.Ing. (Mechanical Engineering Science)
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- Authors: Lasisi, Adedoyin Michael
- Date: 2020
- Subjects: Lasers in aeronautics , Lasers - Industrial applications , Alloys - Mechanical properties , Metal coating
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/479570 , uj:43384
- Description: Abstract: This research study was aimed at researching the synthesis, simulation and characterization of Direct Laser Metal Deposition (DLMD) of Al-Cu-Ti Coatings on Ti-6Al- 4V Alloy for aerospace application. This investigation was accomplished by numerical analysis and experimental techniques. In the category of manufacturing techniques (Additive Manufacturing), the Direct Laser Metal Deposition (DLMD) technique is quite a new field in the industry. This manufacturing technique is flexible, in the sense that it can be used to manufacture working parts or components for bigger assemblies, freeform shapes according to the designer specifications, advanced coatings on the surfaces of working components, and fully solid structures. This research also enquires into the enhanced properties (mechanical, hardness and corrosion) of the modified coating powders (Al-Cu-Ti) on the Titanium alloy (Ti-6Al-4V) and its applications for components and parts enhancements in aerospace industries... , M.Ing. (Mechanical Engineering Science)
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