Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V

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dc.contributor.advisorTait, Robert Ben_ZA
dc.contributor.advisorBecker, Thorstenen_ZA
dc.contributor.authorDhansay, Nur Mohameden_ZA
dc.date.accessioned2017-05-16T08:01:40Z
dc.date.available2017-05-16T08:01:40Z
dc.date.issued2015en_ZA
dc.description.abstractThe focus of this research project was to determine experimentally the fatigue and fracture toughness characteristic, from a fracture mechanics perspective, of Ti-6Al-4V titanium alloy manufactured by Selective Laser Melting (SLM). Three build orientations are considered where a fatigue crack is grown parallel and two are grown perpendicular to the build orientation. The project then endeavours to generate a fracture mechanics based Paris equation from the fatigue crack growth rate results and together with the fracture toughness, fatigue life predictions may be determined based on crack propagation lifetimes. SLM is an Additive Manufacturing (AM) technique whereby an object is fabricated in a layerwise manner via the use of lasers, directly from a 3D CAD model. This process allows for the manufacture of complex designs in its net or near net shape form, which is not possible with conventional manufacturing techniques. There are minimal amounts of material wastage and it potentially eliminates post manufacture machining and processing costs. Ti- 6Al-4V is used in many applications where high strength at low density is required at moderate temperatures. Corrosion resistance qualities of the alloy are also considered for many applications. Some of the applications where this alloy is used include turbine engine components, aircraft structural components, aerospace fasteners, high-performance automotive parts, marine applications, medical implant devices and sports equipment. Due to the large use of the alloy in industry and with the potential benefits of manufacturing by SLM, there is a great need for investigating SLM Ti-6Al-4V as a viable alternative to conventional casting, forging and machining. There is limited literature covering the fatigue crack growth rate and fracture toughness of SLM Ti-6Al-4V and the effect of build orientation on these characteristics. However, it is clear, from the limited available literature that fatigue crack growth rate behaviour is affected by build orientation, and so this project investigates the effect of these orientations, and aims to contribute to understanding why these orientation effects occur. Since there is even less literature available on the fracture toughness of SLM Ti-6Al-4V with respect to build orientation, this project also endeavours to characterise orientation effects on fracture toughness, if any, and compares these with those of conventionally manufacture Ti-6Al-4V.en_ZA
dc.identifier.apacitationDhansay, N. M. (2015). <i>Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Minerals Research. Retrieved from http://hdl.handle.net/11427/24326en_ZA
dc.identifier.chicagocitationDhansay, Nur Mohamed. <i>"Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Minerals Research, 2015. http://hdl.handle.net/11427/24326en_ZA
dc.identifier.citationDhansay, N. 2015. Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Dhansay, Nur Mohamed AB - The focus of this research project was to determine experimentally the fatigue and fracture toughness characteristic, from a fracture mechanics perspective, of Ti-6Al-4V titanium alloy manufactured by Selective Laser Melting (SLM). Three build orientations are considered where a fatigue crack is grown parallel and two are grown perpendicular to the build orientation. The project then endeavours to generate a fracture mechanics based Paris equation from the fatigue crack growth rate results and together with the fracture toughness, fatigue life predictions may be determined based on crack propagation lifetimes. SLM is an Additive Manufacturing (AM) technique whereby an object is fabricated in a layerwise manner via the use of lasers, directly from a 3D CAD model. This process allows for the manufacture of complex designs in its net or near net shape form, which is not possible with conventional manufacturing techniques. There are minimal amounts of material wastage and it potentially eliminates post manufacture machining and processing costs. Ti- 6Al-4V is used in many applications where high strength at low density is required at moderate temperatures. Corrosion resistance qualities of the alloy are also considered for many applications. Some of the applications where this alloy is used include turbine engine components, aircraft structural components, aerospace fasteners, high-performance automotive parts, marine applications, medical implant devices and sports equipment. Due to the large use of the alloy in industry and with the potential benefits of manufacturing by SLM, there is a great need for investigating SLM Ti-6Al-4V as a viable alternative to conventional casting, forging and machining. There is limited literature covering the fatigue crack growth rate and fracture toughness of SLM Ti-6Al-4V and the effect of build orientation on these characteristics. However, it is clear, from the limited available literature that fatigue crack growth rate behaviour is affected by build orientation, and so this project investigates the effect of these orientations, and aims to contribute to understanding why these orientation effects occur. Since there is even less literature available on the fracture toughness of SLM Ti-6Al-4V with respect to build orientation, this project also endeavours to characterise orientation effects on fracture toughness, if any, and compares these with those of conventionally manufacture Ti-6Al-4V. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V TI - Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V UR - http://hdl.handle.net/11427/24326 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/24326
dc.identifier.vancouvercitationDhansay NM. Fracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4V. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Minerals Research, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/24326en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Minerals Researchen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMechanical Engineeringen_ZA
dc.subject.otherMinerals Engineeringen_ZA
dc.titleFracture mechanics based fatigue and fracture toughness evaluation of SLM Ti-6Al-4Ven_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc (Eng)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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