ABSTRACT
Figure 13 shows the general view of the M g - N d phase diagram. It is drawn fol lowing
mainly the last study of it by [163] with correction only of the Mg-r i ch part according to
the investigations by the Baikov Institute of Metallurgy [89, 90, 106]. The phase diagram
is characterised by existence of at least four stable binary compounds, M g 4 1 N d 5 , M g 3 N d ,
M g 2 N d and M g N d . Two of them, M g 3 N d and M g N d , are congruently melting ones, and
the two others, M g 4 1 N d 5 and M g 2 N d , are incongruently melting compounds. The fifth
binary compound M g 1 2 N d , which had also occurred in Mg-r i ch M g - N d alloys, was
recognised in [163] to be a metastable phase. Nevertheless, M g 1 2 N d is also shown in the
phase diagram in Figure 13. The other main features of the M g - N d phase diagram are the
existence of three eutectic equilibria and two eutectoid equilibria. The eutectoid equilibria
correspond to decomposition of either M g 2 N d or the solid solution of the N d high
temperature allotropic form (pNd) during cooling. Two compounds, M g 3 N d and M g N d ,
were suggested to have some homogeneity ranges from the lattice parameters measure-
ments [163], but their boundaries were not established. Therefore, these homogeneity
ranges are shown in the phase diagram in Figure 13 by the dashed lines only.
