In this BSc thesis, we determined the most appropriate quantity of grain refiner in the form of the AlTi3B1 master alloy and the most appropriate grain refiner and melt contact time to form the EN AW-6110A aluminium alloy containing silicon and magnesium as the main alloying elements. The aim was to achieve the grain size of α-Al crystals of below 180 µm. The experimental portion was performed in two series. In the first series, we cast eight samples. Two were comparative samples, while we added different quantities of the master alloy to the other samples. It turned out that the most suitable surcharge is 0.02 weight percent of titanium in the total alloy which yielded the average crystal grain size of 212.6 µm. In the second series, we cast eight samples with 0.02 weight percent of titanium added at different contact times with the melt. The smallest crystal grains were obtained at the contact time of 2 minutes with the average crystal grain size of 157.5 µm. We performed a simple thermal analysis on all samples during the casting and solidification in order to determine the start of the liquidus temperature, the solidification temperature of eutectic mixtures and the solidus temperature. We performed the thermodynamic calculation to produce isopleth maps, characteristic diagrams and Scheil diagrams. Using the above, we determine the phases occurring in our alloy. We observed the samples under the light microscope and determined crystal grain sizes according to the ASTM E 112-96 standard. At the end of the experimental portion, we performed differential scanning calorimetry on all samples whereby we used heating and cooling curves to obtain charasterictic temperatures and solidification and melting enthalpies. In order to evaluate the results, we produced charts to compare the crystal grain sizes and liquidus temperatures.
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