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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Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique
- Authors: Falodun, Oluwasegun Eso , Oke, Samuel Ranti , Obadele, Babatunde Abiodun , Okoro, Avwerosuoghene Moses , Olubambi, Peter Apata
- Date: 2019
- Subjects: Powder metallurgy , Ti6Al4V , SiAlON
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/406789 , uj:34215 , Citation: Falodun, O.E. et al. 2019 : Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique. DOI: https://doi.org/10.1007/s12540-019-00553-3.
- Description: Abstract : The titanium-based composite was fabricated by strengthening Ti6Al4V alloy with addition of SiAlON ceramics utilizing spark plasma sintering technique. Ti6Al4V and SiAlON powders were mixed in a T2F Turbula mixer with different propor- tions (5, 10, 15 and 20 vol%) and the admixed powders were consolidated using spark plasma sintering to produce titanium matrix composites. The characterization of the sintered composites was performed using X-ray diffraction, optical microscopy and scanning electron microscopy. The influence of SiAlON additions on densification, microstructure, microhardness and fracture morphology were investigated on the sintered composites. The experimental results revealed that the densification of the sintered titanium matrix composites was in the range of 95%–98%, which decreased with an increase in SiAlON addition. However, an increase in microhardness values ranging from 363 to 574 HV0.1 was achieved. The microstructure shows that the SiAlON ceramic particle was uniformly distributed within the titanium matrix composites which comprises of a mixture of lamellar colonies with β grain boundaries. The fracture features of all composites exhibit mixed fracture of both intergranular and transgranular fracture mechanism.
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Sinterability studies of high carbon steel powders containing nickel, molybdenum, cobalt and manganese
- Authors: Ramabulana, Khodani
- Date: 2020
- Subjects: Powders , Powder metallurgy , Sintering
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/479636 , uj:43391
- Description: Abstract: The automobile industry is a major consumer of powder metallurgy (PM) components. Occasionally, as in the current case of this investigation, new alloy compositions are specified for production of PM components and research is required to optimize production. This work was aimed at better understanding the influence of alloying additions on the sintering behaviour of the Fe-based powder mix containing high carbon content (up to 0.9 wt.%), and the alloying elements cobalt, molybdenum and nickel. Both the blended elemental and pre-alloyed powder mixtures were investigated whilst attempting to optimize the sintering conditions to achieve a higher density. Dilatometer, DSC with TGA were used to investigate the influence of alloying elements on the sintering behaviour of the Fe powder. Metallographic examination using optical microscopy along with scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS) has been performed in an attempt to relate the results obtained from dilatometer to the microstructure of the alloys. Response surface methodology (RSM) with central composite design (CCD) was also applied to study the influence of sintering parameters (sintering temperature, time and hydrogen content) with the aim of maximising the sintered density of the materials... , M.Tech. (Engineering Metallurgy)
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