Study on the binary intermetallic compounds in the Mg–Ce system

Electron-probe microanalysis (EPMA) and X-ray diffraction (XRD) studies conducted on Mg–38 wt%Ce and Mg–66 wt%Ce alloys demonstrated the existence of two distinct intermetallic phases, Mg 3.6Ce, Mg 3Ce, with the compositions Mg 3.6–3.7Ce, Mg 3.0–3.2Ce, respectively. XRD indicates that Mg 3.6Ce is likely a defect-vacancy structure of Mg 3Ce. The μ-Mg 3Ce phase, with the Mg 3.0–3.3Ce composition and a possible orthorhombic structure, has also been discovered, which is considered a metastable high-temperature form of the Mg 3Ce phase. Based on these results a version of the phase diagram is suggested for the Mg–Ce system in the composition range of 38–70 wt%Ce which correlates well with the solidification microstructures and phases of the two alloys.