Alloying behavior of the rare earth metals with manganese

General features of the phase equilibria for binary and ternary systems formed by rare earth metals (REM or R) with Mn and other d-metals and p-elements (Me) are described and reviewed. On passing from the R-Mn alloys of the light REM to those of the heavy ones, a progressive change in the shape of the phase diagrams and an increasing stability of the intermediate phases (RMn2, RsMn(23), and RMn12) is noticed. In particular, no compounds and a miscibility gap in the liquid state can be observed for La and Ce (which in this case behave like the alkaline earths). In the Pr-Mn and Nd-Mn systems no intermediate phases are stable down to room temperature. The peculiar trend of the R-Mn alloys is, moreover, compared with that exhibited by systems of transition metals close to manganese in the Periodic Table. In the ternary systems R-Mn-Me (the R-Mn-Al, R-Mn-Si and R-Mn-Ge ones were considered) and R-R'-Mn the dependence of the main phase equilibrium characteristics on the atomic radii of REM was observed, too. For the R-R'-Mn alloys a comparison is made between the experimental data (literature data and the authors' results) and those which can be predicted on the basis of the general alloying behavior of REM.