In Situ Investigation of Microstructure Evolution during Solidification of Mg10CaxGd (x=5, 10, 20) Alloys

Mg-Ca-Gd based alloys are investigated as a potential alloy for degradable biomaterials with some promising results. In this investigation the Mg10CaxGd (x=5, 10, 20) were investigated with synchrotron radiation X-ray diffraction during solidification to follow the phase evolution at two different cooling rates at 5 and $50 K \text{min}^{-1}$. All three alloys show formation of α -Mg followed by Mg₂Ca phase, while only Mg10Ca20Gd alloy contained Mg₅Gd phase during solidification. During cooling α -Mg was first observed between 628 and 632°C at a cooling rate of $5 K \text{min}^{-1}$ while this decreased to 620-628°C with the increase in cooling rate to $50 K \text{min}^{-1}$. The change in cooling rate from $5$ to $50 K \text{min}^{-1}$ did not change the types of intermetallic phases observed but resulted in suppressing temperatures at which the intermetallic phases were first detected.