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Browsing by Author "Makoana, Nkutwane W"

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Axial fatigue behaviour of additively manufactured tool steels

Author: Tshabalala, Lerato C ; Sono, Oscar JH ; Makoana, Nkutwane W ; Masindi, J ; Maluleke, O ; Johnston, C ; Masete, Mosimanegape S Date: Jun 2020 Tool steels contain high-nickel and low-carbon content, consisting of alloying elements such as Ni, Co, Mo, Ti and Al. These tool steels exhibit excellent mechanical properties combining high strength with good toughness. The aim was to study ... Read more
Characterization of 17-4PH single tracks produced at different parametric conditions towards increased productivity of LPBF systems—the effect of laser power and spot size upscaling

Author: Makoana, Nkutwane W ; Yadroitsava, I ; Möller, H ; Yadroitsev, I Date: 2018 Global industrial adoption of laser-based powder bed fusion (LPBF) technology is still limited by the production speed, the size of the build envelope, and therefore the maximum part size that can be produced. The cost of LPBF can be driven ... Read more
Coupled heat transfer, fluid flow and solidification kinetics for laser additive manufacturing applications

Author: Khomenko, MD ; Makoana, Nkutwane W ; Pityana, Sisa L ; Mirzade, FKH Date: Jul 2021 A new coupled heat transfer and solidification kinetics model is developed for the optimization of microstructure during laser additive manufacturing applications. The Johnson–Mehl–Avrami–Kolmogorov equation is applied in a self-consistent ... Read more
The effects of LENS process parameters on the behaviour of 17-4 PH stainless steel

Author: Mathoho, Ipfi ; Akinlabi, ET ; Arthur, Nana KK ; Tlotleng, Monnamme ; Makoana, Nkutwane W Date: Feb 2020 17-4 PH stainless steel has proven to be one of the workhorse materials in industries such as aerospace, chemical, and energy. The attraction of this alloy to the aforementioned industries is derived from the fact that 17-4 PH stainless steel ... Read more
Evaluation of single tracks of 17-4PH steel manufactured at different power densities and scanning speeds by selective laser melting

Author: Moller, Hein ; Burger, Herman ; Tlotleng, Monnamme ; Yadroitsev, I ; Makoana, Nkutwane W Date: Nov 2016 In Selective Laser Melting, the initial units produced are single tracks that overlap to create a single layer; from the sequence of layers, a 3D object is manufactured. The properties of the parts produced by SLM depend heavily on the ... Read more c b
Microstructure and mechanical properties of LENS fabricated TiAl structures

Author: Tlotleng, Monnamme ; Makoana, Nkutwane W ; Pityana, Sisa L ; Masina, Bathusile N Date: Nov 2016 It is difficult to produce titanium aluminides (TiAl) components because these materials lack ductility and when used as high temperature structures they fail prematurely due to the inability to self-oxidise. In this study, a 20 by 20 mm cube ... Read more
Multiphysics simulation of thermal phenomena in direct laser metal powder deposition

Author: Pityana, Sisa L ; Tlotleng, Monnamme ; Tshabalala, Lerato C ; Makoana, Nkutwane W ; Botes, A ; Hachemi Amara, EL Date: Nov 2016 The direct laser metal deposition (DLMD) is a recently developed technique for manufacturing solid parts, layer by layer, directly from powder. The process uses a high power laser beam focused onto a metallic substrate to generate a molten ... Read more
Nanoindentation and corrosion behaviour of 410 stainless steel fabricated via additive manufacturing

Author: Lesufi, M ; Akinwamide, SO ; Makoana, Nkutwane W ; Tshabalala, Lerato C ; Olubambi, PA Date: Sep 2022 This study investigates the microstructural, nanomechanical, and corrosion behaviour of different sections of 410 steel fabricated via directed energy deposition technique. The morphology exhibited by the longitudinal and transverse sections ... Read more
Optimization of surface modification for additively manufactured AlSi10Mg using a vibratory polishing surface finisher

Author: Mfusi, Busisiwe J ; Mathe, Ntombizodwa R ; Makoana, Nkutwane W ; Popoola, P Date: Nov 2022 Surface morphology is a significant aspect of a solid material, whether for aesthetic or functional purposes and currently, through different surface modification methods, developments have been dedicated into advancing metallic materials to ... Read more
Post processing of Ti6Al4V manufactured using high power laser powder bed fusion

Author: Makoana, Nkutwane W ; Yadroitsava, I ; Tshabalala, Lerato C ; Yadroitsev, I ; Mathoho, Ipfi ; Pityana, Sisa L Date: Sep 2022 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 ... Read more
Post-processing of direct metal deposited AlCrCoCuFeNi HEA using centrifugal barrel finishing

Author: Modikwe, T ; Maledi, N ; Mathe, Ntombizodwa R ; Pityana, Sisa L ; Dada, M ; Makoana, Nkutwane W Date: Nov 2022 Stainless steels, Ni-based alloys, Ti-based alloys, and more recently high entropy alloys have been used in the aerospace industry to improve the exterior properties of components and coatings that require a fine surface finishing with over ... Read more
Preliminary investigation on selective laser melting of 17-4ph steel using high laser powers of up to 1500w

Author: Makoana, Nkutwane W ; Moller, Heinrich ; Louw, Danie ; Yadroitsev, I Date: Sep 2017 High laser powers of up to 1500W were used to additively manufacture 17-4PH samples. Porosity was measured using the image analysis technique, and all samples are fairly dense with a maximum of 0.42 percent porosity. Read more
Residual stress in laser powder bed fusion

Author: Mugwagwa, L ; Yadroitsava, I ; Makoana, Nkutwane W ; Yadroitsev, I Date: May 2021 Laser powder bed fusion (L-PBF) has great prospects for biomedical, automotive, aerospace and other high-tech industry sectors due to its manufacturing flexibility and design freedom. However, several factors that include high residual stresses, ... Read more
Residual stress, porosity and surface roughness for laser powder bed fusion manufactured Ti6Al4V at high laser powers

Author: Makoana, Nkutwane W ; Yadroitsava, I ; Yadroitsev, I ; Du Plessis, A ; Tshabalala, Lerato C ; Pityana, Sisa L Date: Nov 2021 The use of high-powered lasers presents a unique opportunity to improve the LPBF productivity since a larger beam spot size and higher scanning speeds can be utilized to increase the process build rate. In this study, a custom-built LPBF ... Read more

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Browsing by Author "Makoana, Nkutwane W"

Browsing by Author "Makoana, Nkutwane W"

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