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A Study of the Sintering Behaviour of Ni-Ti Powder Compacts Using Differential Scanning Calorimetry
dc.contributor.author | Whitney, Mark Andrew | |
dc.date.accessioned | 2008-01-25 17:46:16 (GMT) | |
dc.date.available | 2008-01-25 17:46:16 (GMT) | |
dc.date.issued | 2008-01-25T17:46:16Z | |
dc.date.submitted | 2007 | |
dc.identifier.uri | http://hdl.handle.net/10012/3546 | |
dc.description.abstract | A primary purpose of the present work was to develop an experimental technique using Differential Scanning Calorimetry (DSC) capable of elucidating phase formation during sintering of a 50 atomic percent Ni and 50 atomic percent Ti powder compact in order to increase the understanding of the sintering mechanisms that take place during solid state and reactive sintering. Using a variety of Nickel and Titanium powder sizes, effects due to powder size, peak temperature and hold time were studied in situ using DSC, which allowed for a number of qualitative and quantitative relationships to be developed. In studying the eutectoid decomposition of β-Ti using DSC, a simple model was developed (Eq. 4-7) to relate the measured enthalpy of this reaction to the area fraction observed microstructurally. This allowed for the determination of the standard enthalpy for the β-Ti eutectoid decomposition, which was found to be ΔHf = 64.8 J/g. This value, coupled with the measured eutectoid enthalpy, allowed for the determination of the weight fraction of β-Ti present as a function of hold time at 900°C. It was found that the β-Ti removal followed a two-stage parabolic decay. The rate constant for stage I was found to be kI = -0.0347 fβ/(mins)^1/2 and that for stage II, kII = - 0.0123 fβ/(mins)^1/2. A relationship between the enthalpy observed for the combustion reaction versus the fraction of β-Ti present at the time of combustion was also developed (Eq. 4-15). This represents the first published evidence that combustion actually depends on the β-Ti content, which in turn precipitates a melting event significant enough to initiate combustion. | en |
dc.language.iso | en | en |
dc.publisher | University of Waterloo | en |
dc.subject | materials science | en |
dc.subject | reactive sintering | en |
dc.subject | combustion synthesis | en |
dc.subject | differential scanning calorimetry | en |
dc.title | A Study of the Sintering Behaviour of Ni-Ti Powder Compacts Using Differential Scanning Calorimetry | en |
dc.type | Master Thesis | en |
dc.pending | false | en |
dc.subject.program | Mechanical Engineering | en |
uws-etd.degree.department | Mechanical and Mechatronics Engineering | en |
uws-etd.degree | Master of Applied Science | en |
uws.typeOfResource | Text | en |
uws.peerReviewStatus | Unreviewed | en |
uws.scholarLevel | Graduate | en |