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dc.contributor.authorMiddlemas, Michael Roberten_US
dc.date.accessioned2005-09-16T15:08:57Z
dc.date.available2005-09-16T15:08:57Z
dc.date.issued2005-07-18en_US
dc.identifier.urihttp://hdl.handle.net/1853/7190
dc.description.abstractThe alloy Mo-3Si-1B (wt%) may have the fracture toughness and oxidation resistance required for use as jet turbine engine blades. Mo-3Si-1B (wt%) forms a three-phase mixture of and #945;-Moss, A15 (Mo3Si) and T2 (Mo5SiB2). It has been observed that at high-temperatures, the A15 and T2 intermetallics form a oxidation resistant borosilicate glass coating. To achieve the proper combination of mechanical and thermal properties, the material must have a molybdenum matrix with a fine dispersion of intermetallics to produce a continuous protective layer. In this project, reactive sintering of molybdenum, Si3N4 and BN powders was used to create a semi-continuous molybdenum matrix with a fine dispersion of the A15 and T2 intermetallics. Sintering of the materials was further enhanced by the use of submicron-sized reactants. X-ray diffraction analysis was used verify the desired phases were formed. It was determined that formation of the A15 intermetallic phases begins as low as 1200?nd formation of T2 begins at 1300? The reactions are complete by 1400? Samples with bulk densities as high as 95% of theoretical were produced. Scanning electron microscopy images reveal a microstructure with dispersed intermetallics in a semi-continuous molybdenum matrix with grain sizes on the order of 1-4 and #956;m. It was found that by varying parameters such as mixing method and heating rates, it is possible to engineer the final microstructure, changing the level of dispersion of the intermetallics and continuity of the matrix.en_US
dc.format.extent7336047 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectHigh temperature materialsen_US
dc.subjectReactive sintering
dc.subjectMolybdenum silicides
dc.subject.lcshSinteringen_US
dc.subject.lcshMolybdenum alloysen_US
dc.subject.lcshJet engines Design and constructionen_US
dc.subject.lcshHeat resistant materialsen_US
dc.titleA Nitride-Based Reaction for the Formation of a Three-Phase Molybdenum-Silicon-Boron Intermetallic Alloyen_US
dc.typeThesisen_US
dc.description.degreeM.S.en_US
dc.contributor.departmentMaterials Science and Engineeringen_US
dc.description.advisorCommittee Chair: Cochran, Joe; Committee Member: Sanders, Thomas; Committee Member: Sandhage, Kennethen_US


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