The Regularities in Constitution of the Ternary Phase Diagrams of Magnesium Alloys with Two Rare-Earth Metals Belonging to Different Groups (Yttrium Group or Cerium Group)

Abstract

Investigations of the ternary phase diagrams of magnesium with two rare-earth metals from different groups (the yttrium group or the cerium group) are described with the main attention being paid to regions near the Mg corner. In these parts of the ternary phase diagrams, it was found that the magnesium solid solution was in equilibrium with only two binary compounds of magnesium with both rare-earth metals, and in addition, a significant solubility of each rare-earth metal in the most magnesium rich compound of the second rare-earth metal. In ternary Mg-systems involving rare-earth metals of different groups, trends in changes in the constitution in the Mg-region of the diagram as a function of the atomic number of the rare-earth additions were noted. These trends were established by comparing ternary phase diagrams of Mg-containing systems comprising yttrium and a rare-earth metal from the cerium group, and systems comprising samarium (from the cerium group) and a rare-earth metal from the yttrium group.