Powder flow rate influence on laser metal deposited tic on ti-6al-4v
- Authors: Akinlabi, Esther Titilayo , Akinlabi, Stephen A.
- Date: 2016
- Subjects: Powder flow rate , Tic , Ti-6al-4v
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/93277 , uj:20328 , Citation: Akinlabi, E.T. & Akinlabi, S.A. 2016. Powder flow rate influence on laser metal deposited tic on ti-6al-4v.
- Description: Abstract: Laser metal deposition (LMD) presents a suitable substitute for conventional machining of titanium products. It is an additive manufacturing technology used to build prototypes, models, tools, dies and end products. The process is used to manufacture components from materials, which are difficult to machine through conventional methods. Titanium and its alloys are one of the difficult materials to machine since they cause galling on the cutting tool. This paper reports on the material characterization of Laser Metal deposited TiC on Titanium alloy grade 5 and the effect of varying the powder flow rate on the evolving properties of the material. The clads were characterized through microstructural analysis, hardness and degree of porosity. The physical appearances of the samples appeared sound without defect. However, the surfaces of the samples were rough. Furthermore, the average microhardness decreased as the powder flow rate was increased. The microstructural evaluation revealed that the grain size in the deposit zone becomes shorter as the powder flow rate was increased. The microstructure in the heat-affected zone had smaller grain sizes relative to the grain sizes in the deposit zone. In addition, the porosity characterization revealed that the number of pores increases when the powder flow rate increases.
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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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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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