Date of Award

8-15-2019

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Additive Manufacturing, Fatigue, Titanium, Titanium boride, Tribology, Wear

Supervisor

Edrisy, A.

Rights

info:eu-repo/semantics/embargoedAccess

Abstract

While titanium remains an attractive candidate in lightweighting applications, it is often restricted in use due of its poor tribological behaviour and inferior machinability characteristics, leading to its higher relative cost. To address these shortcomings, manufacturers are turning towards alternate, non-conventional manufacturing methods such as additive manufacturing (AM). The mechanical and microstructural properties of alpha, near-commercially pure, titanium made from a novel AM process, termed plasma transferred arc solid free form fabrication, is studied in this research work. Low amounts of titanium-boride (TiB) particles are of interest in as-received samples for their role as a stiffener and strengthener, which can lead to improvements in mechanical and tribological behaviour. This investigation focuses on understanding how the AM build metallurgy and TiB in studied samples influences the mechanical and tribological behaviour of samples. Specially, the research concentrates on wear characterization through ball-on-disk testing and the fatigue behaviour found through rotating-bending testing. Moreover, a final goal of the work was to explore the influence of shot-peening to improve the fatigue and wear behaviour of this material. The investigation revealed that as-received AM blocks showed a near-isotropic behaviour within the structure. Transitional wear behaviour was noted which occurred at the 10N applied loading condition but did not occur in shot-peened samples, which stayed within the first wear regime described. Shot-peening was also found to result in improved fatigue values, increasing the fatigue resistance of samples by 28%, and led to maintained wear resistance with similar COF and wear rate values obtained.

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