ALLOYING BEHAVIOR OF THE RARE-EARTH-METALS WITH MANGANESE

General features of the phase equilibria for binary and ternary system s formed by rare earth metals (REM or R) with Mn and other d-metals an d 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 cha nge in the shape of the phase diagrams and an increasing stability of the intermediate phases (RMn2, RsMn(23), and RMn12) is noticed. In par ticular, 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 e arths). In the Pr-Mn and Nd-Mn systems no intermediate phases are stab le down to room temperature. The peculiar trend of the R-Mn alloys is, moreover, compared with that exhibited by systems of transition metal s close to manganese in the Periodic Table. In the ternary systems R-M n-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 compa rison is made between the experimental data (literature data and the a uthors' results) and those which can be predicted on the basis of the general alloying behavior of REM.