Effect of praseodymium and erbium additions on solidification characteristics, microstructure and mechanical properties of as-cast ZRE1 magnesium alloy

In this research, computer-aided cooling curve thermal analysis, microstructure analysis, hardness measurements, and tensile test were performed to investigate the effect of praseodymium (Pr) and erbium (Er) additions on as-cast ZRE1 magnesium (Mg) alloys. Results from the cooling curve and microstructure analysis showed that praseodymium and erbium altered the grain size of the alloys. Thermal analysis result demonstrated an increased solidification rate with praseodymium and erbium additions. Furthermore, the grain size was reduced by approximately 16% and 15% with the addition of praseodymium and erbium, respectively. Scanning electron microscopy/energy dispersive X-ray spectroscopy results showed that praseodymium combined with the original second phase and formed Mg-Zn-Pr-Ce, and erbium dissolved into the -Mg matrix. Both additives improved the hardness and ultimate tensile strength of the ZRE1 magnesium alloy.