Gas flow rate and powder flow rate effect on properties of laser metal deposited Ti6Al4V
- 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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The role of transverse speed on deposition height and material efficiency in laser deposited titanium alloy
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2013
- Subjects: Additive manufacturing , Laser metal deposition , Material efficiency , Titanium alloy
- Type: Article
- Identifier: uj:4895 , http://hdl.handle.net/10210/12609
- Description: The most commonly used aerospace titanium alloy, Ti6Al4V, was deposited on Ti6Al4V plate of dimension 72 x 72 x5mm. The laser power of 3 kW, powder flow rate of 1.44 g/min and gas flow rate of 4 l/min were used throughout the deposition process. The transverse/ scanning speed was varied between 0.005 to 0.095 m/sec according to established result of the preliminary study that produces full dense and pore free deposits. The mass of the deposited powder was obtained by weight the substrate before deposition and reweighing after deposition. The substrate and the deposits were thoroughly cleaned using wire brush and acetone to remove unmelted powder particles from the surface of the substrate and the deposit. The height and width of the deposits were measured with Venier Caliper and the material efficiencies were determined using developed equations. The effect of the scanning speed on the material efficiency and deposit height were extensively studied and the results showed that for the set of processing parameter used in this study the optimum scanning speed is approximately 0.045 m/sec.
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Characterization of laser deposited Ti6Al4V/TiC composite powders on a Ti6Al4V substrate
- Authors: Mahamood, R. M. , Akinlabi, Esther Titilayo , Shukla, M. , Pityana, S.
- Date: 2014
- Subjects: Laser metal deposition , Material characterization
- Type: Article
- Identifier: uj:4986 , http://hdl.handle.net/10210/13118
- Description: This paper reports the material characterization of Ti6Al4V/TiC composite produced by laser metal deposition. The Ti6Al4V/TiC composites were deposited with a composition ratio of 50 wt.% Ti64l4V and 50 wt.% TiC. The depositions were achieved by delivering the two powders from a powder feeder consisting of two different hoppers and each hopper contains each of the powders. A total of eight experiments were performed, the scanning speed was kept constant at 0.005 m/s and the laser power varied between 0.4 and 3.2 kW. The gas flow rate and the powder flow rates were also kept at constant settings of 1.44 g/min and 1 l/min respectively for each hopper. The deposits were laterally sectioned, metallographically prepared and characterized through microstructural evaluation, microhardness and wear resistance performance. The effects of varying the laser power on the resulting properties of the composites were studied extensively. The microstructure consists of un-melted carbide (UMC) in the matrix of alpha and prior beta grain structure of Ti6Al4V, and in varying degrees in all the samples. The results showed that the microhardness and the wear resistance performance were dependent on the laser power.
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Characterizing the effect of processing parameters on the porosity of laser deposited titanium alloy powder
- Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2014
- Subjects: Laser metal deposition , Medical implants , Porosity , Processing parameters , Titanium alloy
- Type: Article
- Identifier: uj:4739 , ISSN 2078-0966 , http://hdl.handle.net/10210/11725
- Description: Laser Metal Deposition (LMD) is an additive manufacturing technique that produces parts layer by layer directly from the Computer Aided Design (CAD) file. Highly customized parts with complex shapes such as medical implants can well be manufactured using the LMD process. LMD has been used to produce a wide range of patient specific (customized) parts. Porous parts are of particular importance as medical implants because they can potentially aid the healing process and proper integration of the implant with the body tissues. In this research porous samples of titanium alloy (Ti6Al4V) were produced using the LMD process. Spherical shaped Ti6Al4V powder of particle size ranging between 150 to 200 μm was used. The effect of laser power and scanning speed on the shape, size and degree of porosity of the deposited tracks was investigated. The results showed that as the laser power was increased and the scanning speed decreased, the degree of porosity was reduced. The size of the porosity was also found to reduce as the laser power was increased.
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Laser metal deposition of Ti6Al4V/Cu composite : a study of the effect of laser power on the evolving properties
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2014
- Subjects: Porosity , Laser metal deposition , Titanium alloys
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/375937 , uj:4740 , ISSN 978-93-81505-62-5 , http://hdl.handle.net/10210/11726
- Description: A study of the effect of laser power was investigated over the volume of deposited composite, microstructure and microhardness. The laser power was varied between 600 and 1800 W while keeping all other parameters constant. An indication shows that the area and the volume of the deposited composites are directly proportional to the laser power employed. The volume of the deposit obtained falls between 358.6 mm3 and 1009 mm3. The microstructures were analyzed and found that the formation of the Widmanstatten structures improved the hardness of Ti6Al4V/Cu composites. The hardness values of the deposits varied between HV335 and HV490. The percentages of porosities of the samples were also presented and found to have an inverse relationship with the laser power. The results are presented and discussed.
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Microstructures and dry sliding wear characteristics of the laser metal deposited Ti6Al4V/Cu composites
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2015
- Subjects: Dry sliding wear , Laser metal deposition , Microstructures , Titanium composites , Copper composites
- Type: Article
- Identifier: uj:5139 , http://hdl.handle.net/10210/14106
- Description: This paper reports on the investigations conducted on the evolving microstructures and the dry sliding wear of the laser deposited Ti6Al4V/Cu composites. Some selected process parameters were used for the experiments. The laser powers were chosen between 1300 W and 1600 W; scanning speeds were selected between 0.30 m/min and 0.72 m/min while other parameters are as specified in the experimental matrix. It was found that all the composites produced showed good and high-quality microstructures and they exhibited very low or no fusion zones which were as a result of the selected process parameters used. The composite produced at a laser power of 1397 W and a scanning speed of 0.3 m/min was found to show the lowest percentage of wear volume and coefficient of friction; and happened due to the martensitic structure formed during cooling. Results obtained showed that the poor abrasive wear of titanium alloy has been improved with the addition of copper into their lattices.
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Characterising the effect of laser metal deposited Ti6Al4V/Cu composites in simulated body fluid for biomedical application
- Authors: Erinosho, M. F. , Akinlabi, Esther Titilayo , Pityana, S.
- Date: 2015-01-15
- Subjects: Hank’s solution , Laser metal deposition , Surface morphologies , Titanium alloys
- Type: Article
- Identifier: uj:5120 , ISBN 9789384935108 , http://hdl.handle.net/10210/14078
- Description: Ti6Al4V alloy has been known to have very excellent corrosion resistance due to the oxide layer formed on its surface. Due to this property, the alloy is found applicable for biomedical implants. Copper shows an excellent antimicrobial property and has been found to stabilize the immune system. In this study, laser metal deposition of Ti6Al4V powder and Cu powder on Ti6Al4V substrates were conducted by varying the laser power between 600 W and 1800 W while the scanning speed, the powder flow rate and the gas flow rate were kept constant. The surface behaviour and the morphologies of the composites were evaluated under the microscope and the SEM after soaking for 4 hours, 5 days and 2 weeks respectively. The simulated body fluid (hank’s solution) was maintained at normal body temperature of about 37±1oC. The surfaces showed fracture topography with porous bone-like structures and some trivial pitting were observed.
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Laser metal deposition of functionally graded Ti6Al4V/TiC
- Authors: Mahamood, R. M. , Akinlabi, Esther Titilayo
- Date: 2015-06-20
- Subjects: Functionally graded materials , Laser metal deposition , Titanium alloys
- Type: Article
- Identifier: uj:5119 , ISSN 02641275 , http://hdl.handle.net/10210/14077
- Description: Functionally graded materials (FGMs) are advanced materials with improved properties that enable them to withstand severe working environment which the traditional composite materials cannot withstand. FGM found their applications in several areas which include: military,medicine and aerospace. Various manufacturing processes are used to produce functionally graded materials that include: powder metallurgy, physical vapour deposition, chemical vapour deposition process and laser metal deposition process. Laser metal deposition (LMD) process is an additive manufacturing process that can be used to produce functionally graded material directly from the three dimensional (3D) computer aided design (CAD) model of the part in one single process. LMD process is a fairly new manufacturing process and a highly non-linear process. The process parameters are of great importance in LMD process and they need to be optimized for the required application. In this study, functionally graded titanium alloy composite was produced using optimized process parameters for each material combination as obtained through a model that was developed in an initial study and the FGM was characterized throughmetallurgical, mechanical and tribological studies. The results showthat the produced FGM has improved properties when compared to those produced at constant processing parameters for all material combinations.
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Characterization of functionally graded commercially pure titanium (CPTI) and titanium carbide (TiC) powders
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2015-07-01
- Subjects: Functional graded materials , Laser metal deposition , Titanium , Titanium carbide
- Type: Article
- Identifier: uj:5136 , ISBN 9789881404701 , http://hdl.handle.net/10210/14102
- Description: Functionally Graded Materials (FGM) are advanced materials fabricated using additive manufacturing techniques. It belongs to a class of advanced material characterization in which the properties of the material composition is varied. The resulting property of the composite is always different from the properties of the individual material employed in the formation of the composite. They are known to also exhibit good mechanical and chemical properties and as such, are used for different industrial applications. One of the techniques employed in the fabrication of FGMs is called Laser Metal Deposition (LMD) technique. It uses laser beam to melt powder material on a substrate forming a melt pool that solidifies upon cooling. This paper reports on the material characterization of functionally graded Titanium and Titanium Carbide (TiC) powders deposited on Titanium substrate by laser metal deposition approach. The formed deposits were fabricated by varying the processing parameters such as laser power, scanning speed and the powder flow rate. From the result obtained, the microstructures showed that the laser power has much influence on the grain growth of the material. In addition, with the SEM analysis of the microstructure since the percentages of the titanium and titanium carbide were varied, it was observed that the sharp boundaries of the Titanium Carbide were reduced greatly and this resulting effect can be attributed to the thermal effect of the laser. The microstructures further revealed that as the percentage of TiC decreases, it becomes more difficult to see the TiC as a different material in the composite, emphasizing this as one of the best characteristics of functionally graded materials, which is the elimination of sharp interfaces and layers. Furthermore, it was observed that the laser power has great influence on the evolving hardness of the material compared to the TiC content.
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Influence of scanning speed and energy density on the evolving properties of laser deposited Ti6Al4V/Cu composites
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2015-07-01
- Subjects: Laser metal deposition , Microhardness , Titanium composites , Copper composites
- Type: Article
- Identifier: uj:5131 , ISBN 9789881404701 , http://hdl.handle.net/10210/14094
- Description: Titanium is a light metal and finds application majorly in the aerospace and bio medicals. This paper presents the influence of scanning speed and energy density on the evolving microstructure and microhardness of laser deposited Ti6Al4V/Cu composites. The laser power, powder flow rates and gas flow rates were kept constant while varying the scanning speed. From the microscopic analysis, α acicular structures were found growing from the top of the cross section of the composite and broke into the β-phase and the grain boundary of the (α+β) phase, and found to disappear gradually as the scanning speed increases. Widmanstettan was also found in all the samples. Sample S21 of energy density 240 J/mm2 deposited with a laser power of 1200 W and a scanning speed of 5 mm/secs shows the highest hardness value of 541±20 HV0.5 while Sample S27 of energy density of 48 J/mm2 deposited with a laser power of 1200 W and a scanning speed of 25 mm/secs shows the lowest hardness value of 405±12 HV0.5. This was attributed to the Cu content added and plays a vital role in stabilizing and strengthening the β-phase.
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Advanced coating: laser metal deposition of aluminium powder on titanium substrate
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2016
- Subjects: Heat affected zone , Laser metal deposition , Powder metallurgy
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93266 , uj:20325 , Citation: Akinlabi, E.T. & Akinlabi, S.A. 2016. Advanced coating: laser metal deposition of aluminium powder on titanium substrate.
- Description: Abstract: Laser Metal Deposition (LMD) is an additive manufacturing technique, which can be used to produce solid components from a Computer Aided Design (CAD) model. The LMD process makes use of feeding powder, which is supported by the shielding gas, into the melt pool that is produced by sharply focused collimated laser beam on the substrate. This study employs aluminium powder in its molten state on titanium substrate through the LMD process. The aluminium powder was deposited at varying laser scanning speeds while the laser power and gas flow rate were kept constant. The presence of alpha phase grains were observed in the microstructures of samples at a lower scanning speed and the beta phase grains at a higher laser scanning speed. It was found that the geometrical properties of the deposits, that is; the width, height and the Heat Affected Zone (HAZ) of each sample decreased as the scan speed increases resulting from the laser-material interaction. The microhardness and the corrosion rates of each sample increased as the laser scanning speed increases.
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Behaviour of laser metal deposited Ti6Al4V/Cu composites in hank’s solution for biocompatibility properties
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Hank’s solution , Laser metal deposition , Microhardness
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/215427 , uj:21416 , Citation: Erinosho, M.F., Akinlabi, E.T & Pityana, S. 2016. Behaviour of laser metal deposited Ti6Al4V/Cu composites in hank’s solution for biocompatibility properties.
- Description: Abstract: Ti6Al4V alloy is a well-known material for biomedical application due to the very excellent corrosion resistance it possessed. Copper is an excellent antimicrobial property and has been found to stabilize the immune system of the body activities. In this present study, laser metal deposition of Ti6Al4V/Cu composites have been conducted by varying the laser power between 600 W and 1800 W while the scanning speed of 0.005 m/s and other process parameters as depicted in the experimental matrix were kept constant. Widmanstettan structures were observed in all the samples at high magnification and lose their coarseness as the laser power increases. The microhardness values of the deposited composites were varied between HV335 ± 27 μm and HV490 ± 73 μm. The surface behaviour and the morphologies of the composites were evaluated under the SEM after soaking for 2 weeks. The simulated body fluid (hank’s solution) was maintained at normal body temperature of about 37±1oC. The surfaces showed fracture topography with porous bone-like and snowflake structures.
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Characterization of laser metal deposited 316L stainless steel
- Authors: Bayode, A. , Akinlabi, Esther Titilayo , Pityana, S.
- Date: 2016
- Subjects: Laser metal deposition , Microhardnes , Stainless steel
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/92382 , uj:20223 , Citation: Bayode, A., Akinlabi, E.T. & Pityana, S. 2016. Characterization of laser metal deposited 316L stainless steel.
- Description: Abstract: Laser metal deposition (LMD) is an innovative manufacturing technique that uses laser to melt powders to fabricate fully dense components layer by layer. It is capable of processing different metallic powders and can also be used for consolidating different powder to produce custom alloys or functionally graded materials (FGM). The properties of laser processed materials is dependent on the final microstructure of the parts which in turn is dependent on the LMD processing parameters. This study investigates the effects of laser power on the structural integrity, microstructure and microhardness of laser deposited 316L stainless steel. The result showed that the laser power has much influence on the evolving microstructure and microhardness of the components. The average microhardness of the samples were observed to decrease as the laser power increased due to grain coarsening.
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Effect of laser power on the microstructural behaviour and strength of modified laser deposited Ti6Al4V+CU alloy for medical application
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Laser metal deposition , Microstructure , Microhardness
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/121883 , uj:20577 , Citation: Erinosho, M.F. & Akinlabi, E.T. 2016. Effect of laser power on the microstructural behaviour and strength of modified laser deposited Ti6Al4V+CU alloy for medical application.
- Description: Abstract: Please refer to full text to view abstract
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Effect of powder density variation on premixed Ti-6Al-4V and Cu composites during laser metal deposition
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Powder density , Laser metal deposition , Titanium alloys , Copper
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/123406 , uj:20787 , Citation: Erinosho, M.F., Akinlabi, E.T & Pityana, S. 2016. Effect of powder density variation on premixed Ti-6Al-4V and Cu composites during laser metal deposition.
- Description: Abstract: This paper reports the effect of powder density variation on the premixed Ti-6Al-4V/Cu and Ti-6Al-4V/2Cu Composites. Two sets of experiment were conducted in this study. Five deposits each were made for the two premixed composites. Laser powers were varied between 600 W and 1700 W while a scanning speed of 0.3 m/min is kept constant throughout the experiment. Investigations were conducted on the microstructures and microhardness of the laser deposited premixed Ti-6Al-4V/Cu and Ti-6Al-4V/2Cu composites. It was found that the evolving microstructures of the composites were characterised with the formation of macroscopic banding and Widmanstatten; and disappears as it grows towards the fusion zone (FZ) and this could be attributed to the changes in the distribution of heat input. Sample A2 of premixed Ti-6Al-4V/Cu composite gives the highest hardness of 393 ± 6.36VHN0.5 while sample B4 of premixed Ti-6Al-4V/2Cu composites depicts the highest hardness value of 373 ± 9.18VHN0.5.
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Effect of scanning speed and powder flow rate on the evolving properties of laser metal deposited ti-6al-4v/cu composites
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Hardness , High pfr , Laser metal deposition , Microstructure , Porosity , Volume of deposited composite
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/93307 , uj:20331 , Citation: Erinosho, M.F., Akinlabi, E.T. & Pityana, S. 2016. Effect of scanning speed and powder flow rate on the evolving properties of laser metal deposited ti-6al-4v/cu composites.
- Description: Abstract: In Laser Metal Deposition (LMD), good bonding between two similar or dissimilar materials can be achieved if the interrelationships between the processing parameters are well understood. LMD samples of titanium alloy, Ti-6Al-4V and copper, Cu were produced by varying the scanning speed and keeping other parameters constant. The deposited samples were characterized through the volume of deposited composites, microstructure, microhardness and the degree of porosity. The effect of the optimized high (powder flow rate) PFR, scanning speed varying from 0.06 m/min to 1.2 m/min and a constant power of 1kW led to a degree of porosity on the deposited composites. The varying percentages of porosities in the samples have an advance merit effect in the implantation of bones in animal and human. It was found that the existence of pores reduced as the scanning speed increases. The Vickers mirohardness was observed to increase with an increase in the scanning speed which shows an improvement in the properties of the Ti-6Al-4V/Cu composites. At low scanning velocity, the microstructure appears coarse due to the high rate of powder deposited at the same power of 1kW. The α-phase acicular microstructure decreases in size and thickness with an increase in the scanning speed. Widmanstätten structure was found in the scanning electron microscopy analyses. The results show that high PFR and low scanning speed have significantly influenced the evolving properties of the deposited composites.
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Estimation of surface topography and wear loss of laser metal deposited Ti6Al4V and Cu
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo
- Date: 2016
- Subjects: Laser metal deposition , Microstructure , Surface roughness topography
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/214314 , uj:21265 , Citation: Erinosho, M.F & Akinlabi, E.T. 2016. Estimation of surface topography and wear loss of laser metal deposited Ti6Al4V and Cu.
- Description: Abstract: The atomic force microscopy (AFM) analysis is a process that involves the detailed analyses of the surface of a three dimensional sample piece. A good image is always generated on such a sample once the settings are implemented correctly. And as such, the amplitude set point played a vital role in achieving a better image. For surface engineering applications, a small proportion of Cu has been added to Ti6Al4V alloy and deposited using a 2kW Ytterbium Fibre Laser. This paper presents the evolving microstructures and the surface topographies of the laser deposited Ti6Al4V/Cu alloys. The formation and the output of the microstructure depend on the laser processing parameters employed. The α-Ti lamella formed was observed to gain coarseness with respect to the increase in the laser power. The migration of the β-phase has been impeded during solidification due to the low strain hardening effect posed by the α-Ti lamella thereby limiting the further dislocation of the β-phase within the crystal structure. A clear picture of the height, amplitude and the phase shift of the scanned sample were viewed before a capture can be made. A correlation between wear loss and surface roughness has been established among the laser deposited samples.
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Experimental and numerical analysis of geometrical properties of laser metal deposited titanium
- Authors: Akinlabi, Esther Titilayo , Tayob, Mohammed A. , Pietra, Francesco
- Date: 2016
- Subjects: Ansys , Heat-Affected zone , Laser metal deposition , Microhardness , Microstructure , Porosity , Powder flow rate , Titanium
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93300 , uj:20330 , Citation: Akinlabi, E.T., Tayob, M.A. & Pietra, F. 2016. Experimental and numerical analysis of geometrical properties of laser metal deposited titanium.
- Description: Abstract: Laser metal deposition (LMD) is a manufacturing process, which can be used to manufacture a complete, fully functional part by building it up layer-by-layer using the data from a Computer-Aided-Design (CAD) file. The layer-by-layer addition can also be used to rebuild worn-out sections of existing parts, as well as to deposit protective coatings to protect parts in surface engineering. The process involves laser heating a substrate, on which a metal powder is deposited. The powder solidifies, when mixed with the substrate, thereby creating a metallurgical bond. In order to produce parts with high geometrical tolerances and desirable material properties, the process parameters have to be carefully controlled. Since the LMD process requires the interaction of parameters, it is not always easy to predict the output geometry. In this paper, the laser metal deposition process was modelled in ANSYS Parametric- Design-Language (APDL), using a transient thermal analysis, in order to determine the geometrical properties of the clad, that is, the width and the height of the resulting clad. The simulated results were then compared experimentally by depositing Commercially Pure (CP) titanium powder onto a Ti-6Al-4V substrate, in order to verify the simulation. The varying parameter in the experimental process was the powder flow rate, which was varied between 0.5-2.5g/min. In addition to the geometrical properties, the microstructure, microhardness; and the porosity levels of the deposited clads were also analyzed, in order to better determine the clad quality and integrity. The model showed good agreement in predicting both the height and the width of the clads. Porosity was noticed in all the samples with the exception of the clad deposited at the lowest powder flow rate setting of 0.5 g/min. An increase in the powder flow rate also led to a smaller fusion zone, due to a lower laser-material interaction period, which was the result of the increase in the quantity of powder causing attenuation of the beam, and less laser power being absorbed by the substrate. The smaller fusion zone meant that the clads could not bond to the substrate properly, which led to the clad in the sample produced with the highest powder flow rate falling off the substrate. There was a significant increase in the microhardness of the clad zone, which was due to a combination of alloying with Ti- 6Al-4V and a change in the microstructure to an acicular alpha martensite microstructure; while the Heat-Affected-Zone (HAZ) in the substrate only showed a slight increase in microhardness.
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Exploration of microstructure and wear behaviours of laser metal deposited Ti6Al4V/Cu composites
- Authors: Erinosho, Mutiu F. , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Dry sliding wear , Laser metal deposition , Microstructures
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/215408 , uj:21415 , Citation: Erinosho, M.F., Akinlabi, E.T & Pityana, S. 2016. Exploration of microstructure and wear behaviours of laser metal deposited Ti6Al4V/Cu composites.
- Description: Abstract: This paper reports on the investigations conducted on the evolving microstructures and the dry sliding wear of the laser deposited Ti6Al4V/Cu composites. Some selected process parameters were used for the experiments. The laser powers were chosen between 1300 W and 1600 W; scanning speeds were selected between 0.30 m/min and 0.72 m/min while other parameters are as specified in the experimental matrix. It was found that all the composites produced showed good and high-quality microstructures and they exhibited very low or no fusion zones which were as a result of the selected process parameters used. The α-phase region of the composites was found to be harder than the β-phase region. During the composites cooling, the β-phase field transformed to the basal planes of the hexagonal α-phase thereby creating a lower diffusion coefficient of the α-phase as compared to the β-phase counterpart. The Ti6Al4V/Cu composite produced at a laser power of 1397 W and a scanning speed of 0.3 m/min was found to show the lowest percentage of wear volume and coefficient of friction; and happened due to the martensitic structure formed during cooling. Results obtained showed that the poor abrasive wear of titanium alloy has been improved with the addition of copper into their lattices.
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Influence of laser power on the deposition Ti64l4V/W composite
- Authors: Ndou, Ndivhuwo , Akinlabi, Esther Titilayo , Pityana, Sisa
- Date: 2016
- Subjects: Heat affected zone , Laser metal deposition
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/214837 , uj:21331 , Citation: Ndou, N., Akinlabi, E.T & Pityana, S. 2016. Influence of laser power on the deposition Ti64l4V/W composite.
- Description: Abstract: In this study of laser power on deposited of Ti64l4V/W was investigated. The energy flow rates were varied while every single other parameter were kept at a steady. The evolving microstructure and the hardness of the composites were studied and reported in this study. The study established that the laser metal deposition process is suitable for producing acceptable bonding between a deposited zone and a substrate zone. The hardness values of the deposits varied from 377HV to 719HV. The laser power directly influences the hardness and the microstructure. Scanning electron microscopy (SEM) was utilised to characterise the microstructure of the composite layer formed on the surface of the Ti6Al4V substrate. The microstructure of all the composite layers delivered by the LMD procedure has upgraded properties in connection to that of the Ti64l4V substrate.
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