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Influence of Cooling Rates on Temperatures Phase Transitions and on Microstructure of Aluminium Alloy EN AW-5083

The casting of different forms and dimensions of aluminium alloy EN WA-5083 test samples and the usage of different types of mould materials resulted in achieving different cooling rates of samples. The methods used were simple thermal analysis, using casting into a measuring cell made by the Croning process and using casting into a cone-shaped measuring cell, as well as simultaneous thermal analysis using the method of differential scanning calorimetry. Significant temperature phase transitions and times of solidification were determined, and the dependence model of the solidification time on the sample cooling rate was obtained. Determining the mean number of grains per unit area on samples after having performed the simple thermal analysis and differential scanning calorimetry makes it possible to develop a dependence model of the mean number of grains per unit area on the cooling rate. These models are the basis for carrying out numerical simulations of solidification and microstructure development in the cone-shaped measuring cell, and the comparison of the distribution of the mean number of grains per unit area obtained by simulation with the one obtained experimentally. The obtained results represent a part of the preliminary tests of the microstructure development of industrially cast ingots of EN AW-5083 alloy depending on the local ingot cooling rate.

EN AW-5083 aluminium alloy; numerical simulation; thermal analysis methods; mean number of grains per unit area

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