The erosion of titanium aluminide intermetallic alloys

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dc.contributor.advisorBall, Anthonyen_ZA
dc.contributor.advisorLang, Candyen_ZA
dc.contributor.authorHoward, Robert Llewellynen_ZA
dc.date.accessioned2016-03-04T16:31:45Z
dc.date.available2016-03-04T16:31:45Z
dc.date.issued1995en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe erosion behaviour of titanium aluminide intermetallic alloys has not been widely reported in the scientific literature and is part of the current international research effort aimed at exploiting these materials for turbine engine and automotive applications. In the present study titanium aluminides have been subjected to both solid particle erosion and cavitation erosion. The erosion rates have been measured and the damage mechanisms have been identified and discussed in terms of the microstructures and mechanical properties of the titanium aluminide alloys. This has been achieved with a variety of investigative techniques, including electron microscopy, mechanical testing and microstructural examination; and, where necessary, the erosion performance of other materials have been evaluated for comparison. In particle erosion, conducted with air blast rigs at room temperature and at elevated temperature, the titanium aluminide alloys exhibit a ductile mode of material removal, and their limited strain to fracture results in higher particle erosion rates than those for 304 stainless steel. Heat treatment to produce changes in microstructure and hardness does not significantly affect particle erosion performance, and elevated temperature tests reveal an increase in particle erosion rate with increasing temperature. In cavitation erosion, the titanium aluminide alloys exhibit a ductile mode of damage accumulation and material loss, and the rates of material loss are lower than those for other engineering materials such as 304 stainless steel and some hardmetal grades which are currently used in erosive environments. The mechanism of cavitation erosion of the Ti₃Al-based alloy involves the accumulation of strain in phase boundary regions and the preferential removal of the more brittle component of the microstructure. For the Ti₃Al-based alloy, cavitation erosion resistance increases with an increase in hardness produced by heat treatment. The TiAl-based alloys exhibit twinning during the initial stages of cavitation, which is characteristic of the high strain rate deformation of TiAl-based alloys, followed by substantial work hardening and preferential material loss from phase interfaces and twinned regions.en_ZA
dc.identifier.apacitationHoward, R. L. (1995). <i>The erosion of titanium aluminide intermetallic alloys</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/17434en_ZA
dc.identifier.chicagocitationHoward, Robert Llewellyn. <i>"The erosion of titanium aluminide intermetallic alloys."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1995. http://hdl.handle.net/11427/17434en_ZA
dc.identifier.citationHoward, R. 1995. The erosion of titanium aluminide intermetallic alloys. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Howard, Robert Llewellyn AB - The erosion behaviour of titanium aluminide intermetallic alloys has not been widely reported in the scientific literature and is part of the current international research effort aimed at exploiting these materials for turbine engine and automotive applications. In the present study titanium aluminides have been subjected to both solid particle erosion and cavitation erosion. The erosion rates have been measured and the damage mechanisms have been identified and discussed in terms of the microstructures and mechanical properties of the titanium aluminide alloys. This has been achieved with a variety of investigative techniques, including electron microscopy, mechanical testing and microstructural examination; and, where necessary, the erosion performance of other materials have been evaluated for comparison. In particle erosion, conducted with air blast rigs at room temperature and at elevated temperature, the titanium aluminide alloys exhibit a ductile mode of material removal, and their limited strain to fracture results in higher particle erosion rates than those for 304 stainless steel. Heat treatment to produce changes in microstructure and hardness does not significantly affect particle erosion performance, and elevated temperature tests reveal an increase in particle erosion rate with increasing temperature. In cavitation erosion, the titanium aluminide alloys exhibit a ductile mode of damage accumulation and material loss, and the rates of material loss are lower than those for other engineering materials such as 304 stainless steel and some hardmetal grades which are currently used in erosive environments. The mechanism of cavitation erosion of the Ti₃Al-based alloy involves the accumulation of strain in phase boundary regions and the preferential removal of the more brittle component of the microstructure. For the Ti₃Al-based alloy, cavitation erosion resistance increases with an increase in hardness produced by heat treatment. The TiAl-based alloys exhibit twinning during the initial stages of cavitation, which is characteristic of the high strain rate deformation of TiAl-based alloys, followed by substantial work hardening and preferential material loss from phase interfaces and twinned regions. DA - 1995 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1995 T1 - The erosion of titanium aluminide intermetallic alloys TI - The erosion of titanium aluminide intermetallic alloys UR - http://hdl.handle.net/11427/17434 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17434
dc.identifier.vancouvercitationHoward RL. The erosion of titanium aluminide intermetallic alloys. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1995 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17434en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Materials Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMaterials Engineeringen_ZA
dc.titleThe erosion of titanium aluminide intermetallic alloysen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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