The milling of tin bronze with a Cu-24.6wt%Sn composition

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dc.contributor.advisorLang, Candyen_ZA
dc.contributor.authorWilliams, Garthen_ZA
dc.date.accessioned2014-10-11T11:34:25Z
dc.date.available2014-10-11T11:34:25Z
dc.date.issued1997en_ZA
dc.descriptionIncludes bibliographies.en_ZA
dc.description.abstractThe effects of high energy milling on tin bronze with the composition Cu-24.6wtSn have been examined using hardness testing, optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffraction. High energy milling has caused mechanical alloying of an elemental copper and tin powder blend, and mechanical milling of a cast powder and a melt quenched powder. Nanocrystalline grains with a size between 5 nm and 50 nm have been directly observed in the final milled powder. The powder consist of the a phase and 8 phase and is partially amorphous. An extension of the solid solution solubility has also been detected due to milling. The formation of the metastable tin-rich 11 phase has been observed in the intermediate stage of mechanical alloying of the elemental powder blend due to the higher diffusivity of tin in copper over copper in tin. The formation of the 11 phase during mechanical alloying of tin bronze with the composition Cu-24.6wtSn has not been reported before. The morphological development of the three initial powders has proceeded by different mechanisms during milling due to the different hardness and toughness of the starting powders. Milling of the elemental powder blend and the cast powder proceeds via classic mechanisms for milling of ductile powders and brittle powders respectively, while milling of the tougher melt quenched powder proceeds via a combination of the two mechanisms. An attempt to process the milled powder into a bulk state using various thermomechanical techniques while still retaining a nanocrystalline grain size has not succeeded. The high diffusivity of the material at elevated temperatures has led to grain growth into the micrometer range even at relatively low thermo-mechanical processing temperatures. The milled powders have poor compaction properties due to the highly deformed structure and therefore the processed material has poor properties compared to a cast material.en_ZA
dc.identifier.apacitationWilliams, G. (1997). <i>The milling of tin bronze with a Cu-24.6wt%Sn composition</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/8280en_ZA
dc.identifier.chicagocitationWilliams, Garth. <i>"The milling of tin bronze with a Cu-24.6wt%Sn composition."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1997. http://hdl.handle.net/11427/8280en_ZA
dc.identifier.citationWilliams, G. 1997. The milling of tin bronze with a Cu-24.6wt%Sn composition. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Williams, Garth AB - The effects of high energy milling on tin bronze with the composition Cu-24.6wtSn have been examined using hardness testing, optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffraction. High energy milling has caused mechanical alloying of an elemental copper and tin powder blend, and mechanical milling of a cast powder and a melt quenched powder. Nanocrystalline grains with a size between 5 nm and 50 nm have been directly observed in the final milled powder. The powder consist of the a phase and 8 phase and is partially amorphous. An extension of the solid solution solubility has also been detected due to milling. The formation of the metastable tin-rich 11 phase has been observed in the intermediate stage of mechanical alloying of the elemental powder blend due to the higher diffusivity of tin in copper over copper in tin. The formation of the 11 phase during mechanical alloying of tin bronze with the composition Cu-24.6wtSn has not been reported before. The morphological development of the three initial powders has proceeded by different mechanisms during milling due to the different hardness and toughness of the starting powders. Milling of the elemental powder blend and the cast powder proceeds via classic mechanisms for milling of ductile powders and brittle powders respectively, while milling of the tougher melt quenched powder proceeds via a combination of the two mechanisms. An attempt to process the milled powder into a bulk state using various thermomechanical techniques while still retaining a nanocrystalline grain size has not succeeded. The high diffusivity of the material at elevated temperatures has led to grain growth into the micrometer range even at relatively low thermo-mechanical processing temperatures. The milled powders have poor compaction properties due to the highly deformed structure and therefore the processed material has poor properties compared to a cast material. DA - 1997 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1997 T1 - The milling of tin bronze with a Cu-24.6wt%Sn composition TI - The milling of tin bronze with a Cu-24.6wt%Sn composition UR - http://hdl.handle.net/11427/8280 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/8280
dc.identifier.vancouvercitationWilliams G. The milling of tin bronze with a Cu-24.6wt%Sn composition. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1997 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/8280en_ZA
dc.language.isoeng
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 milling of tin bronze with a Cu-24.6wt%Sn compositionen_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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