In-situ thermal analysis and macroscopical characterization of Mg–xCa and Mg–0.5Ca–xZn alloy systems

This research described the identification phases by thermal analysis and microscopy inspection of Mg– x Ca and Mg–0.5%Ca– x Zn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg 2 Ca intermetallic phase at around 520 °C in addition to α-Mg phase. First derivative curves of alloys after the addition of Zn to Mg–0.5Ca alloy reveals three peaks related to α-Mg, Mg 2 Ca and Ca 2 Mg 6 Zn 3 for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg 2 Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 °C for Mg–0.5Ca–9Zn which was identified as Mg 51 Zn 20 . Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures ( T N – T DCP ) increased by adding Ca and Zn in Mg–Ca and Mg–Ca–Zn systems.