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252 results on '"Pityana, Sisa"'

60. Post processing of Ti6Al4V manufactured using high power laser powder bed fusion

Author

Makoana, Nkutwane Washington, Yadroitsava, Ina, Tshabalala, Lerato, Yadroitsev, Igor, Mathoho, Ipfi, and Pityana, Sisa

Abstract

To further increase the adoption of additive manufacturing in the industry, it is important to leverage the technology’s potential for serial production to drive down the cost of manufacturing. The use of high-powered laser beam has been envisaged as the potential technique to improve the productivity of additive manufacturing processes such as laser powder bed fusion. Since a large beam spot size is normally used at high laser power, the rougher surfaces obtained in the as-built condition can be a limitation for medical applications. As such, post processing of the parts manufactured is required to enhance the surface quality. This study investigates the effect of post processing on the surface roughness and mechanical properties of Ti6Al4V manufactured at high laser power. The samples manufactured using developed process parameters were subjected to hot isostatic press annealing and polished by centrifugal barrel finishing. The surface roughness and mechanical properties obtained are presented and discussed., Transactions on Additive Manufacturing Meets Medicine, Vol. 4 No. 1 (2022): Trans. AMMM

Published
2022
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88. Scanning Speed Effect on the Microstructure, Hardness, Wear, and Corrosion Performance of VC-Cr3C2 Reinforced Laser Claddings on Steel Baseplate for Tillage Application.

Author

Aramide, Basiru, Jamiru, Tamber, Pityana, Sisa, Sadiku, Rotimi, and Popoola, Patricia

Abstract

The poor tribological property and the high susceptibility of steel material used in mining and tillage tools to wear and corrosion attack during mining and tillage operations have brought about the need to enhance its property. Hence, this study examined the effect of the laser scanning speed on the FeCrV15 coatings' hardness, microstructure, and wear behaviour. In-situ VC-Cr3C2 coatings were made in this comparative study through laser-deposition of high carbon ferrochrome FeCrV15 powder at varying scanning speeds, viz: 8, 10, and 13 mm/s on steel baseplates. The morphologies of the coatings were analysed with the Scanning Electron Microscope, equipped with Energy Dispersion Spectroscopy (SEM/EDS), Optical microscope, X-ray diffractometer, Vicker microhardness tester, Anton Paar Tribometer, and Autolab Potentiostat. The study shows defect-free samples with good metallurgical bonding between the clads and the substrate and even distribution of VC-Cr3C2 phases in the microstructure. By increasing the scanning speed, the hardness of FeCrV15 coating reduces, and so is its resistance to corrosion and sliding wear. The production of In-situ VC-Cr3C2 reinforcement is attained by laser deposition of high carbon ferrochrome FeCrV15 powder on steel baseplate, which stands in opposition against abrasive wear, thereby increasing the durability of tillage and mining tools. [ABSTRACT FROM AUTHOR]

Published
2022
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92. Scanning Speed Effect on the Microstructure, Hardness, Wear, and Corrosion Performance of VC-Cr3C2Reinforced Laser Claddings on Steel Baseplate for Tillage Application

Author

Aramide, Basiru, Jamiru, Tamber, Pityana, Sisa, Sadiku, Rotimi, and Popoola, Patricia

Abstract

Abstract: The poor tribological property and the high susceptibility of steel material used in mining and tillage tools to wear and corrosion attack during mining and tillage operations have brought about the need to enhance its property. Hence, this study examined the effect of the laser scanning speed on the FeCrV15 coatings’ hardness, microstructure, and wear behaviour. In-situ VC-Cr3C2coatings were made in this comparative study through laser-deposition of high carbon ferrochrome FeCrV15 powder at varying scanning speeds, viz: 8, 10, and 13 mm/s on steel baseplates. The morphologies of the coatings were analysed with the Scanning Electron Microscope, equipped with Energy Dispersion Spectroscopy (SEM/EDS), Optical microscope, X-ray diffractometer, Vicker microhardness tester, Anton Paar Tribometer, and Autolab Potentiostat. The study shows defect-free samples with good metallurgical bonding between the clads and the substrate and even distribution of VC-Cr3C2phases in the microstructure. By increasing the scanning speed, the hardness of FeCrV15 coating reduces, and so is its resistance to corrosion and sliding wear. The production of In-situ VC-Cr3C2reinforcement is attained by laser deposition of high carbon ferrochrome FeCrV15 powder on steel baseplate, which stands in opposition against abrasive wear, thereby increasing the durability of tillage and mining tools. Graphical Abstract:

Published
2022
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93. Laser Based Additive Manufacturing Technology for Fabrication of Titanium Aluminide-Based Composites in Aerospace Component Applications

Author

Pityana, Sisa, Aramide, Fatai, Popoola, Olawale, Popoola, Patricia, and Raji, Sadiq

Subjects
Technology & Engineering
Abstract

Titanium aluminides has the potential of replacing nickel-based superalloys in the aerospace industries because its density is almost half that of nickel-based alloys. Nevertheless, the room temperature properties (ductility) have made the wider application of this class of intermetallic alloy far from being realized. This has led to various research been carried out in adjusting the production processing and/or material through alloying, heat treatment, ingot metallurgy, powder metallurgy and most recently additive manufacturing processing. One of the additive manufacturing processing of titanium aluminide is laser engineered net shaping (LENS). It is used to produce components from powders by melting and forming on a substrate based on a computer-aided design (CAD) to shape the components. This contribution will focus on the laser processing of titanium aluminides components for aerospace applications. Also, the challenges confronting this processing techniques as well as suggested finding to solve the problems would be outlined. The objective of this work is to present an insight into how titanium aluminides components have been developed by researchers with emphasis on aerospace applications.

Published
2019

94. Laser ButtWelding of Thin Ti6Al4V Sheets: Effects of Welding Parameters.

Author

Omoniyi, Peter, Mahamood, Rasheedat, Arthur, Nana, Pityana, Sisa, Skhosane, Samuel, Yasuhiro Okamoto, Togo Shinonaga, Maina, Martin, Tien-Chien Jen, and Akinlabi, Esther

Subjects
WELDING, TITANIUM alloys, MANUFACTURING industries, MICROHARDNESS, TENSILE strength, FRACTOGRAPHY
Abstract

Titanium and its alloys, particularly Ti6Al4V, which is widely utilized in the marine and aerospace industries, have played a vital role in different manufacturing industries. An efficient and cost-effective way of joining this metal is by laser welding. The effect of laser power and welding speed on the tensile, microhardness, and microstructure of Ti6Al4V alloy is investigated in this paper. Results show that the microhardness is highest at the fusion zone and reduces towards the base metal. The microstructure at the fusion zone shows a transformed needle-like lamellar α phase, with a martensitic ff' phase observed within the heat affected zone. Results of tensile tests show an improved tensile strength compared to the base metal. [ABSTRACT FROM AUTHOR]

Published
2021
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