ABSTRACT
Nd-r ich crystals after crystallisation were considered in it to be the phase M g 1 2 N d and the
Nd-r ich phase in eutectoid and the fine eutectic was considered to be the phase M g 4 1 N d 5 .
Figure 48c demonstrates the eutectic in the hypoeutectic M g - S m alloy. The similarity
with the M g - N d eutectic is evident and this fact confirms similar formulas of the R E - r i c h
compounds forming eutectics in both systems, M g 4 1 L n 5 . Figure 48d clearly demonstrates
a plate-like eutectic in the M g - G d system. In the systems with the next elements of the
lanthanum series M g - T b , M g - D y , M g - H o and M g - E r eutectics were of approximately
the same constitution and some were coarser than that in the M g - G d system. A s an
example of them, in Figure 48e eutectic in the hypoeutectic M g - D y alloy is shown. The
last Figure 48f demonstrates inner constitution of the Tm-rich phase in the eutectic of the
M g - T m system. Its cheese-like character confirms eutectoid decomposition of the
unknown phase Mg^Tm^. in the system.
