Showing items 1 - 16 of 16

Your selections:

Investigation of mechanical properties of friction and laser welded Ti-6Al-4V rods.

- Tlale, Thabo, Mashinini, P. M., Mukhawana, D. M.

Gas flow rate and powder flow rate effect on properties of laser metal deposited Ti6Al4V

- Pityana, Sisa, Mahamood, Rasheedat M., Akinlabi, Esther Titilayo, Shukla, Mukul

  • Authors: Pityana, Sisa , Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul
  • Date: 2013
  • Subjects: Gas flow rate , Microhardness , Microstructure , Powder flow rate , Laser metal deposition , Additive manufacturing technology
  • Type: Article
  • Identifier: uj:4849 , http://hdl.handle.net/10210/12516
  • Description: Tracks of Ti6Al4V powder were deposited on Ti6Al4V substrate using Laser Metal Deposition (LMD) process, an Additive Manufacturing (AM) manufacturing technology, at a laser power and scanning speed maintained at 1.8 kW and 0.005 m/s respectively. The powder flow rate and the gas flow rate were varied to study their effect on the physical, metallurgical and mechanical properties of the deposits. The physical properties studied are: the track width, the track height and the deposit weight. The mechanical property studied is the Microhardness profiling using Microhardness indenter at a load of 500g and dwelling time of 15 μm. The metallurgical property studied is the microstructure using the Optical microscopy. This study revealed that as the powder flow rate was increased, the track width, track height and the deposit weight were increased while as the powder flow rate was increased, the track width, track height and the deposit weight decreased. The results are presented and discussed in detail.
  • Full Text:

TIG welding of Ti6Al4V alloy: Microstructure, fractography, tensile and microhardness data

- Omoniyi, Peter, Mahamood, Modupe, Jen, Tien-Chien, Akinlabi, Esther

Data on assessment and exploratory statistical correlation data analysis of sintered Nd :YAG laser welded 2507 duplex stainless steel

- Olanipekun, Ayorinde Tayo, Mashinini, Peter Madindwa, Maledi, Nthabiseng Beauty

Analysis of the influence of the laser power on the microstructure and properties of titanium alloy - reinforced boron carbide matrix composite (Ti6Al4V-B4C)

- Ogunlana, Musibau O., Akinlabi, Esther Titilayo, Erinosho, Mutiu F.

Influence of scanning speed on the intermetallic produced in-situ in laser metal deposited TiC/Ti6Al4V composite

- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo

Process parameter optimization for laser metal deposited Ti6Al4V/TiC composites

- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo

  • Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo
  • Date: 2015-01-15
  • Subjects: Laser material deposition , Microhardness , Process parameters , Titanium composites , Aluminum composites
  • Type: Article
  • Identifier: uj:5134 , ISBN 9789384935108 , http://hdl.handle.net/10210/14100
  • Description: Laser material deposition process is an additive manufacturing technology that is used to produce functional parts directly from the three dimensional (3D) model of the part. It offers a lot of advantages in the surface modification of components, in the repair of existing worn parts, as well as for building parts that is made up of composites and functionally graded materials. This is possible because the laser metal deposition process can handle more than one material simultaneously. Processing parameters are of great importance in achieving the desired properties. Ti6Al4V is the most widely used titanium alloy in the aerospace industry. This is because of its excellent properties. However, the wear resistance behavior of these materials is not impressive because of the surface damage that occurs when they are used in applications that involves contact loadings. In this study, the effect of laser power and scanning velocity on the microstructure, the microhardness and the wear resistance properties of Ti6Al4V/TiC composites has been thoroughly investigated in order to optimize these process parameters. The Ti6Al4V/TiC composites were laser deposited with a composition ratio of 50 W% Ti64 and 50 W% TiC and at 50% overlap percentage. The laser power was varied from 1 to 3.8 kW and the scanning speed was varied between 0.03 and 0.1 m/s. The results shows that the optimum process parameters is at a laser power of about 2.0 kW and the scanning speed of about 0.055 m/s.
  • Full Text: false

Laser metal deposition of Ti6Al4V : a study on the effect of laser power on microstructure and microhardness

- Mahamood, Rasheedat M., Akinlabi, Esther Titilayo, Shukla, Mukul, Pityana, Sisa

  • Authors: Mahamood, Rasheedat M. , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
  • Date: 2013
  • Subjects: Laser metal deposition process , Laser power , Ti6Al4V , Macroscopic banding , Microhardness , Microstructure
  • Type: Article
  • Identifier: uj:4896 , http://hdl.handle.net/10210/12610
  • Description: The effect of laser power on the resulting microstructure and microhardness of laser metal deposited Ti6Al4V powder on Ti6Al4V substrate has been investigated. The tracks were deposited using 99.6 % pure Ti6Al4V powder of particle size ranging between 150 - 200 μm on 99.6% Ti6Al4V substrate. The laser power was varied between 0.8 - 3.0 kW while the scanning speed, powder flow rate and the gas flow rate were kept at the values of 0.005 m/sec, 1.44 g/min and 4 l /min respectively. The microstructure and the microhardness were studied using the optical microscope and the Vickers hardness tester respectively. Layer band or macroscopic banding was observed in all the samples which is phenomenon as it was only reported in the literature for multi-layer deposits. The literature attributed re-melting of the previous layers by the succeeding layers as being responsible for their formation. This study has revealed that this band could be as a result of shrinkage happening in the fusion zone as a result of the interaction of the deposited powder and the melt pool created by the substrate material. This study also reveals the relationship between the microstructure, the average microhardness and the laser power which are comprehensively discussed. The higher the laser power, the lower the density of columnar prior beta grain structure. Also the average microhardness increases as the laser power increases.
  • Full Text:

Comparative characterization of P91 and 10CrMo9-10 creep resistant steel welds

- Madyira, D. M., Liebenberg, J. A., Kaymacki, A.

  • Authors: Madyira, D. M. , Liebenberg, J. A. , Kaymacki, A.
  • Date: 2017
  • Subjects: P91 , 0CrMo9-10 , Microhardness
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/247448 , uj:25693 , Citation: Madyira, D.M., Liebenberg, J.A. & Kaymacki, A. 2017. Comparative characterization of P91 and 10CrMo9-10 creep resistant steel welds.
  • Description: Abstract: , Abstract: P91 and 10CrMo9-10 creep resistant steels are critical to the performance of boiler tubes and power generating plants in general. Components made from these materials are mainly joined by welding. This paper reports on the comparative study of the effect of TIG and SMAW welding on the mechanical performance of P91 and 10CrMo9-10. TIG was used for root welding while SMAW was used for weld filling of V-butt joints. Specimens of the two alloys prepared using recommended welding procedures are evaluated using optical microscopy and Vickers micro hardness assessment. Some specimens were post weld heat treated while others were not. Post weld heat treated (PWHT) specimens exhibited similar properties as the corresponding base materials for both steels. TIG welding resulted in significant grain size reduction in both steels. PWHT produced more consistent grain structure, which is favorable.
  • Full Text:

Influence of laser power on the surfacing microstructures and microhardness properties of Ti-6Al-4V-Cu alloys using the ytterbium fiber laser

- Erinosho, Mutiu F., Akinlabi, Esther Titilayo

Behaviour of laser metal deposited Ti6Al4V/Cu composites in hank’s solution for biocompatibility properties

- Erinosho, Mutiu F., Akinlabi, Esther Titilayo, Pityana, Sisa

Influence of scanning speed and energy density on the evolving properties of laser deposited Ti6Al4V/Cu composites

- Erinosho, Mutiu F., Akinlabi, Esther Titilayo, Pityana, Sisa

  • 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.
  • Full Text:

Effect of laser power on the microstructural behaviour and strength of modified laser deposited Ti6Al4V+CU alloy for medical application

- Erinosho, Mutiu F., Akinlabi, Esther Titilayo

Microstructural development during mechanical forming of steel sheets

- Akinlabi, Stephen A., Akinlabi, Esther Titilayo

  • Authors: Akinlabi, Stephen A. , Akinlabi, Esther Titilayo
  • Date: 2013
  • Subjects: Microhardness , Metal forming , Steel - Deformation
  • Type: Article
  • Identifier: uj:4852 , ISBN 978-988-19251-0-7 , http://hdl.handle.net/10210/12519
  • Description: Metal forming is used synonymously with deformation, a process during which an object gets changed due to the applied force. These changes can either be reversible or irreversible depending on the type of material; size and geometry of the object and the magnitude of the applied force to the object. This paper reports the microstructural development after mechanical forming of steel sheet material by varying the applied loads. The microstructural evaluations showed that the applied loads employed caused an increase in the magnitude of the grain sizes in each loaded specimen. Furthermore, the increase in the grain size of the microstructure was observed to be directly proportional to the loads applied. In addition, the microhardness values of the cross sections investigated were found to increase with the applied loads. Hence, the grain size growth and the hardness were linearly dependent on the applied loads, and this implies that there is a correlation between the applied loads and the resulting microstructure of the material and the hardness of the material.
  • Full Text:

Experimental and numerical analysis of geometrical properties of laser metal deposited titanium

- Akinlabi, Esther Titilayo, Tayob, Mohammed A., Pietra, Francesco

  • 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.
  • Full Text:

Forming behaviour of steel sheets after mechanical and laser beam forming

- Akinlabi, Esther Titilayo, Shukla, M., Akinlabi, S. A., Kanyanga, S. B., Chizyuka, C. M.

  • Authors: Akinlabi, Esther Titilayo , Shukla, M. , Akinlabi, S. A. , Kanyanga, S. B. , Chizyuka, C. M.
  • Date: 2014
  • Subjects: Laser beam forming , Mechanical forming , Microhardness , Microstructure , Tensile testing , Steel plates - Mechanical properties
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/379024 , uj:4998 , http://hdl.handle.net/10210/13136
  • Description: This paper reports the influencing factors and the characteristic behaviour of steel plates during both the mechanical forming and laser beam forming processes. Samples of the steel sheets were mechanically bent to 120 mm curvatures using a 20 ton capacity eccentric mechanical press at room temperature and also with the laser beam using a 4.4 kW Nd: YAG laser system at a scan speed of 1.9 m/min, beam diameter of 12 mm, laser power of 1.7 kW at 25% beam overlap using argon for cooling the irradiated surfaces. The chemical composition of both the as-received material and the formed samples were analysed by emission spectroscopy to quantify the changes in the elemental composition. The result shows a percentage increase in the carbon after the mechanical and laser forming processes when compared to the parent material. This can be attributed to the enhancement resulting from the forming processes. The formed samples were further characterized through microstructure, microhardness and tensile tests. The microstructural characterisation of the samples revealed that the grains of the mechanically formed and laser formed components are elongated, it was also observed that there is an increase in the pearlite grains of the laser formed components resulting from the thermal heating during the laser process. The microhardness profiles of the formed components showed that there is a significant percentage increase in the Vickers microhardness values of the laser formed samples when compared to the mechanically formed samples and with respect to the parent material. The laser beam forming process can be considered a more appropriate forming process in terms of the resulting material properties in this regard.
  • Full Text:
  • 1
  • Disclaimer
  • Privacy
  • Copyright
  • Contact