Effect of Cu and Zn on the melting and transformation temperatures of Pr and Gd

Phase equilibria in the R-rich regions of the R-Cu and R-Zn binary systems (R=Pr and Gd) have been investigated by differential thermal analysis, X-ra y powder diffractometry, metallographic analysis and quantitative electron probe microanalysis. In these regions, the lowering (DeltaT) of the melting and transformation temperatures of the rare earth metals by addition of co pper and zinc resulted in eutectic and catatectic or eutectoidal type react ions. The DeltaT observed in these systems are discussed and compared with those reported in the literature for the binary systems of Pr and Gd with M g and with the elements from the 9th to the 14th group of the Periodic Tabl e. In order to complete this systematics, a few Pr-rich Pr-Cd alloys have a lso been prepared and analysed. (C) 2001 Elsevier Science B.V. All rights r eserved.