Laser metal deposition of titanium aluminide composites : a review
- Authors: Abdulrahman, Kamardeen O. , Akinlabi, Esther Titilayo , Mahamood, Rasheedat M. , Pityana, Sisa , Tlotleng, Monnamme
- Date: 2018
- Subjects: Titanium aluminide composites , Laser metal deposition , Additive manufacturing processes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/291200 , uj:31618 , Citation: Abdulrahman, K.O. et al. 2018. Laser metal deposition of titanium aluminide composites : a review.
- Description: Abstract: Development of additive manufacturing (AM) from three dimensional printers with ability of producing parts having no need for tooling continue to wax stronger in the manufacturing field. Laser metal deposition, a technique in AM is usually employed to create solid components from model of computer aided design (CAD). Feeding powder supported by shielding gas employed by this technique, is injected into a melt pool produced by accurately focused laser beam on a substrate. This paper discusses some of the AM technologies available, review on laser metal deposition of titanium aluminide on other metals and alloys, relationship between the processing parameters and structural and mechanical properties
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Microstructures, hardness and bioactivity of hydroxyapatite coatings deposited by direct laser melting process
- Authors: Tlotleng, Monnamme , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2014
- Subjects: Direct laser melting , Laser power , Hydroxyapatite coatings
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/376152 , uj:4994 , http://hdl.handle.net/10210/13129
- Description: Hydroxyapatite (HAP) coatings on bioinert metals such as Ti–6Al–4V are necessary for biomedical applications. Together, HAP and Ti–6Al–4V are biocompatible and bioactive. The challenges of depositing HAP on Ti–6Al–4V with traditional thermal spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little dilution. The microstructural and mechanical properties, chemical composition and bio-activities of the produced coatings were studied with optical microscopy, scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and Vickers hardness machine, and by immersion test in Hanks' solution. The results showed that the choice of the laser power has much influence on the evolving microstructure, the mechanical properties and the retainment of HAP on the surface of the coating. Also, the choice of laser power of 750Wled to no dilution. The microhardness results inferred a strong intermetallic– ceramic interfacial bonding; which meant that the 750 W coating could survive long in service. Also, the coating was softer at the surface and stronger in the heat affected zones. Hence, this process parameter setting can be considered as an optimal setting. The soak tests revealed that the surface of the coating had unmelted crystals of HAP. The CaP ratio conducted on the soaked coating was 2.00 which corresponded to tetra calcium phosphate. This coating seems attractive for metallic implant applications.
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Microstructural and mechanical evaluation of laser-assisted cold sprayed bio-ceramic coatings : potential use for biomedical applications
- Authors: Tlotleng, Monnamme , Akinlabi, Esther Titilayo , Shukla, Mukul , Pityana, Sisa
- Date: 2014
- Subjects: Titanium , Laser power , Cold spray , Laser-assisted cold spray , Hydroxyapatite
- Type: Article
- Identifier: uj:5135 , ISSN 1544-1016 , http://hdl.handle.net/10210/14101
- Description: Bio-composite coatings of 20 wt.%, HAP and 80 wt.%, HAP were synthesized on Ti-6Al-4V substrates using LACS technique. The coatings were produced with a laser power of 2.5 kW, powder-laser spot trailing by 5 s. The coatings were analyzed for the microstructures, microhardness, composition, and bio-corrosion using SEM-EDS, XRD, hardness tester, and Metrohm PGSTAT101 machine. SEM images indicated least pores and crack-free coating with dark-spots of Ti-HAP for the 20 wt.%, HAP as opposed to the 80 wt.%, HAP coating which was solid, porous and finely cracked and had semi-melted Ti-HAP particles. The EDS mappings showed high content of HAP for the 80 wt.%, HAP coating. The diffraction patterns were similar, even though the Ti-HAP peak was broader in the 80 wt.%, HAP coating and the HAP intensities were lower for this coating except for the (004) peak. The hardness values taken at the interface inferred that the 80 wt.%, HAP coating was least bonded. It was possible to conclude that when this phase material increased the hardness dropped considerably. The bio-corrosion tests indicated that the presence of HAP in coating leads to a kinetically active coating as opposed to pure titanium coating.
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