The erosion of ultrafine WC-Co

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dc.contributor.advisorAllen, Colinen_ZA
dc.contributor.authorPugsley, Victoria Antoniettaen_ZA
dc.date.accessioned2016-05-24T09:08:28Z
dc.date.available2016-05-24T09:08:28Z
dc.date.issued1999en_ZA
dc.description.abstractA series of four ultrafine WC-Co alloys of varying cobalt contents has been sintered from powder produced through the spray conversion process. The materials have been characterised and subjected to slurry erosion and cavitation erosion. A further twelve WC-Co alloys of varying grain sizes and cobalt contents have been produced through conventional processes and subjected to the same tests in order to provide data for comparison. The erosion resistance of all the grades tested was found to increase with decreasing grain size, both under cavitation erosion and slurry erosion conditions. Furthermore, a transition from a localised material removal mechanism to a bulk material removal mechanism was observed in both erosive systems as the WC grain size of the material decreased below about lμm. The erosion resistance of sub-micron materials was found to be considerably more sensitive to bulk deformation parameters than that of coarser materials. As a result, ultrafine grades subjected to slurry erosion or cavitation erosion were found to exhibit lifetimes up to seven times greater than those of the best-performing materials with grain sizes above 1 μm. This increase in erosion resistance was achieved without any significant drop in fracture toupness. Significant differences were observed between the response of WC-Co to the two erosive systems, particularly in those materials exhibiting a localised erosion response. Under slurry erosion conditions, these materials displayed increasing erosion resistance with decreasing cobalt content, and both the cobalt and WC phases responded to erosive attack. Under cavitation erosion conditions, however, the opposite trend was observed, and only the cobalt phase responded to erosive attack. Materials exhibiting a bulk erosion response responded in a similar fashion to both forms of erosive attack, although cavitation erosion produced damage to a greater depth. The effect of defects on material performance was found to depend critically on the erosive system.en_ZA
dc.identifier.apacitationPugsley, V. A. (1999). <i>The erosion of ultrafine WC-Co</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/19805en_ZA
dc.identifier.chicagocitationPugsley, Victoria Antonietta. <i>"The erosion of ultrafine WC-Co."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1999. http://hdl.handle.net/11427/19805en_ZA
dc.identifier.citationPugsley, V. 1999. The erosion of ultrafine WC-Co. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Pugsley, Victoria Antonietta AB - A series of four ultrafine WC-Co alloys of varying cobalt contents has been sintered from powder produced through the spray conversion process. The materials have been characterised and subjected to slurry erosion and cavitation erosion. A further twelve WC-Co alloys of varying grain sizes and cobalt contents have been produced through conventional processes and subjected to the same tests in order to provide data for comparison. The erosion resistance of all the grades tested was found to increase with decreasing grain size, both under cavitation erosion and slurry erosion conditions. Furthermore, a transition from a localised material removal mechanism to a bulk material removal mechanism was observed in both erosive systems as the WC grain size of the material decreased below about lμm. The erosion resistance of sub-micron materials was found to be considerably more sensitive to bulk deformation parameters than that of coarser materials. As a result, ultrafine grades subjected to slurry erosion or cavitation erosion were found to exhibit lifetimes up to seven times greater than those of the best-performing materials with grain sizes above 1 μm. This increase in erosion resistance was achieved without any significant drop in fracture toupness. Significant differences were observed between the response of WC-Co to the two erosive systems, particularly in those materials exhibiting a localised erosion response. Under slurry erosion conditions, these materials displayed increasing erosion resistance with decreasing cobalt content, and both the cobalt and WC phases responded to erosive attack. Under cavitation erosion conditions, however, the opposite trend was observed, and only the cobalt phase responded to erosive attack. Materials exhibiting a bulk erosion response responded in a similar fashion to both forms of erosive attack, although cavitation erosion produced damage to a greater depth. The effect of defects on material performance was found to depend critically on the erosive system. DA - 1999 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1999 T1 - The erosion of ultrafine WC-Co TI - The erosion of ultrafine WC-Co UR - http://hdl.handle.net/11427/19805 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/19805
dc.identifier.vancouvercitationPugsley VA. The erosion of ultrafine WC-Co. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1999 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/19805en_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 ultrafine WC-Coen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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