Analyses of impurities in cast magnesium-rare earth elements alloys

Microstructure analyses of impurities in binary Mg–3%RE and Mg–8%RE alloys are presented. Light microscopy and scanning electron microscopy (SEM+EDX) techniques were used to characterize the investigated material. In microstructure, besides α-Mg solution and α+Mg12RE eutectic, some intermetallic compounds with different morphology (needle-like, square-like) were observed. X-ray phase analyses showed that intermetallic compounds were RE Si and 3 2 RE2Fe14Si3. Their location in axis of primaryα-Mg dendrites suggests that some parts of them may act as heterogeneous nucleation sits for magnesium.