Thermophysical properties of cast aluminium alloys

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Kemian tekniikan korkeakoulu | Master's thesis
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Date
2014-06-23
Department
Major/Subject
Materials Engineering
Mcode
KE3004
Degree programme
MTE - Materiaalitekniikan koulutusohjelma
Language
en
Pages
92
Series
Abstract
Thermophysical properties of several binary aluminium - silicon alloys castings were studied using Differential scanning calorimetry and Dilatometry. In this research is investigated the behaviour of the material during the first heating after casting. The temperature range examined is 100 – 500 °C with a scan rate of 10 K/min. Therefore, only phase transformations of the solid-state are involved. The results have shown an evident thermal effect around 270 – 300 °C for all the samples in both DSC and DIL analysis. DSC analysis has determined that is involved an exothermal process, and the same process in dilatometry analysis causes a quick increase of the coefficient of thermal expansion. This thermal effect reaches the maximum value for an amount of silicon of 6-9%wt. The reason of this peak is related with the transformation of the oversaturated α-aluminium solid solution present in the alloy (even for hypereutectic compositions). The oversaturation is due to the rapid solidification that occur during the casting process.
Description
Supervisor
Gasik, Michael
Thesis advisor
Bilotsky, Yevgen
Keywords
aluminium casting alloy, Al-Si, differential scanning calorimetry, dilatometry, thermal analysis
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