ABSTRACT
Many of the investigations were devoted to the ternary and more complicated phase
diagrams of magnesium alloys with individual rare earth metals. Mos t of them were
undertaken in connection with the development and application of new magnesium
commercial alloys with improved mechanical characteristics for application at ambient and
elevated temperatures. Meanwhile, the scientific aspect in most studies was also
significant. The list of the investigated ternary and quaternary phase diagrams is presented
in Table 23. It includes only the systems which are known by the author as those having
been investigated. A t the same time it is probable that some unknown systems of M g with
rare earth metals have been investigated by others. However, the number of such investi-
gations unknown to the author must not be great. Anyway, very many phase diagrams have
been studied already, and their examinations enable the main generalisations on their
constitution to be deduced reliably. Most investigations were limited by the concentration
areas adjoining the M g corners of the phase diagrams, and the main objects in them were
extension of M g solid solution region, the phases being in equilibrium with M g solid
solution, the liquidus surface and the invariant equilibria with M g solid solution partici-
pation. Another remarkable feature of the systems chosen for the investigations is their
connection with development of commercial alloys. This is the reason why the systems
studied are those with the most often used rare earth elements in magnesium alloys, lantha-
num, cerium, neodymium, yttrium. A few systems studied were also with samarium,
gadolinium and dysprosium which were only recently recognised as quite effective in
strengthening M g .
