Characteristics of eutectic precipitations in selected magnesium cast alloys

The paper focuses on characterization of eutectic precipitations in three magnesium alloys (MSR-B, ZRE1 and WE43) containing rare earth elements. It was shown, that the structure of the tested alloys in a cast state consists of globular grains of the α-Mg solid solution and eutectic areas of different chemical composition and morphology. An untypical influence of the pouring temperature on the eutectic precipitations area fraction was observed. This phenomenon can be explained by impoverishment of the eutectic-forming elements in the areas of the slowest solidification. This results from the fact, that at the highest pouring temperature a considerable amount of eutectic forms in places solidified as the first.