Abstract

In this thesis, the solidification behaviors of AZ9ID, AM60B and AE44 commercial magnesium alloys have been studied experimentally by differential scanning calorimeter (DSC) and optical microscopy. The effect of different cooling rates on the transition temperatures and microstructures were analyzed. It was found that the effect of cooling rate on the solidus temperature is more significant than on the liquidus. The solidus temperature decreases clearly with increasing cooling rates, but for the liquidus temperature there is slightly increasing trend. The latent heat of solidification was also calculated and found that it increases when the cooling rate increases. Thermodynamic calculations were made using FactSage along with VLGM database and were compared with the experimental findings as well as with the literature data. Thermodynamic calculations were also utilized to understand the microstructures as well as the phase distribution. The microstructural details of as-cast and post-DSC samples have also been investigated using optical microscope. Finally, relationships between cooling rate and transition temperature as well as between cooling rate and latent heat of solidification have been established based on the general power law. Using these relationships it is possible to predict the transition temperatures and latent heat of solidification of these alloys at high cooling rates