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Investigation of Transition State Phenomenon of Metals during Solidification
Ort / Verlag
ProQuest Dissertations & Theses
Erscheinungsjahr
2009
Quelle
ProQuest Dissertations & Theses A&I
Beschreibungen/Notizen
Solidification is the phase transition process from liquid state to solid state, which is important in the material preparation and formation. Investigations on phenomenon and law of solidification process have sustained for thousands of years. Till now, considerably less is known about their earliest stages compared with the behavior of bulk crystals, when they nucleate and grow from a liquid. This present work investigates the temperature dependence of viscosity and the liquid structure near the liquidus, and the energy changes during the solidification process. This work discovers phenomenon of transition state near the liquidus, which provides the theory and experimental data for the solidification. The viscosity of the eutectic Pb38.1Sn61.9 alloy has been measured by a torsional oscillation viscometer using three different crucibles which are made of the materials of highly sintered alumina (Al2O3), quartz (SiO2), and graphite (C), respectively. The roughness of crucibles has effect on the viscosity. The