Masters Degrees (Mechanical and Mechatronic Engineering)

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Browsing Masters Degrees (Mechanical and Mechatronic Engineering) by Subject "Additive manufacturing -- South Africa"

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    Near-beta titanium alloys produced using laser powder-bed fusion.
    (Stellenbosch : Stellenbosch University, 2023-03) Rudolph, SM; Becker, Thorsten Hermann ; Ter Haar, GM; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: β titanium alloys are used extensively in the aerospace industry to fulfil a multitude of applications due to their favorable properties, including the exhibition of high strength, workability, corrosion resistance, interchangeable combinations of strength and toughness, and ability to be heat treated over a wide range. However, little to no literature is available on the printability and mechanical performance of β titanium alloys subjected to additive manufacturing (AM), which is largely used for rapid prototyping and the production of complex components. Therefore, in this research, the printability and consequent mechanical performance of two β titanium alloys, viz. Ti-5Al-5V-5Mo-3Cr (Ti-5-5-5-3) and Ti-15Mo-3Nb- 3Al-0.2Si (Beta 21S), are considered whereby laser powder bed fusion is the means of manufacture. The process parameters were optimized experimentally in which the region of experimentation was determined using simulation software. The density was evaluated using the Archimedes’ principle. Pores were analyzed using optical microscopy. Additionally, the resulting microstructures were studied using scanning electron microscopy to further characterize the two alloys. The hardness and tensile properties of the as-built samples were investigated. A strong correlation was found between those reported and that of literature. The results demonstrate performance competitive with traditionally manufactured products, but more complex builds require investigation to alleviate uncertainties regarding the performance thereof. Additionally, the processing windows developed correlate with literature and provide insight into the combinations of process parameters which yield dense parts. The research presented herein reports the methods used to characterize the printability and mechanical performance demonstrated by commercially available β titanium alloys, Ti-5-5-5-3 and Beta 21S, produced by laser powder bed fusion.